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BaBar Glossary Search Tool

Entire Glossary

A fitting algorithm for DCH tracks. This track fitter uses a full five parameter helix fit and does not assume that the tracks come form the origin of the x-y plane.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Detector/Trigger/Level3/mtg-970130/cretsi-dcx-fitting.txt)

Instrumented Flux Return

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Detector/IFR/IFR.html)

Untriggered Personality Card

Interruption of beam arriving to a detector in order to allow people to enter the radiaton protection area and work on the detector itself.

This is a module used in the BaBar Electromagnetic Calorimeter (EMC) Data AcQuisition (DAQ) system. ADC Boards will be used both in the barrel and end-cap of the EMC.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Detector/DAQ/Calorimeter/WriteUps/ADB.pdf)

No actual packages are included in a newly created test release. The addpkg command, checks out a package from the CVS repository and adds it to the test release.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/srt1/srt1.html#addpkg)

AMD is a chip designed that produces Intel 386 compatible CPUs. BaBar is evaluating support for them currently.

Reference Link (http://www.amd.com/us-en/)

The database file systems are accessed remotely via the Advanced Multi-threaded Server, (AMS), using a network protocal. To the user this means that a federation must be created and used on a machine that has the AMS daemon running.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/objectivity1/objectivity1.html#terms)

This was a component of the BaBar detector in the earlier design phases. It would have been primarily a particle identification device. It was not actually built.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/TDR/)

EPICS (Experimental Physics and Industrial Control Systems) application which provides and interface to software alarms.

Reference Link (http://www.aps.anl.gov/asd/controls/epics/EpicsDocumentation/ExtensionsManuals/AlarmHandler/alhUserGuide.pdf)

Complete set of events taken by BaBar passing Data Quality criteria.

The history of some of the data collected by EPICS. It is indexed by time.

This is a BaBar environment defined command. It's main purpose is to set the OO_FD_BOOT environment variable to point to the off-line copy of ambient database. This command must be executed from a release or immediate subdirectory of one.

Objectivity federation used to store data from ambient, conditions, and configurations databases. Ambientboot receives daily updates of data from ir2boot and weekly updates from MASTER. Ambientboot was created primarily to reduce the load on the ir2boot federation from the application working with the ambient data. If the application does not need ambient data from last 24 hours, it should be run against ambientboot instead of ir2boot.

1999/2000 analysis federation. Used to run analysis based on data from 1999/2000.

This is a BaBar environment defined command. It's main purpose is to set the OO_FD_BOOT environment variable to point to the productuction database by the name of analboot. This command must be executed from a release or immediate subdirectory of one.

This is a BaBar environment defined command. It's main purpose is to set the OO_FD_BOOT environment variable to point to the productuction database by the name of analboot2. This command must be executed from a release or immediate subdirectory of one.

2000/2001 analysis federation. Used to run analysis based on data from 2000/2001.

An electronics board where analog signals are converted to digital signals for readout. In the EMC, the ADB converts the readout of 12 individual channels.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Detector/DAQ/Calorimeter/WriteUps/EMCDAQDoc.html#ADB)

A loudspeaker, connected to a computer, in the BaBar counting room, which gives important messages to the shifters.

Positive voltage wire in drift chamber to which electrons are attracted.

For every particle in nature there exists an anti-particle (antimatter) with same mass and spin, but opposite electric charge, baryon number, strangeness, lepton number etc. The interaction of a particle with its anti-particle results in their annihilation and release of energy. Although anti-particles and anti-atoms (anti-hydrogen) can be made experimentally, there is no evidence for the existence of large amounts of antimatter in nature.

Reference Link (http://livefromcern.web.cern.ch/livefromcern/antimatter/)

An application framework is a flexible, general purpose encompassing structure, that enforces certain well designed standards of code behavior. An example of an application framework is Microsoft's Foundation Classes.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/framework1/framework1.html)

A uniform framework interface is accomplished by having each module class inherit from the class AppModule.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/framework1/framework1.html)

ATOM is your telecommunications representative through whom you can arrange for changes to your phone and voice mail services to be made.

Reference Link (http://www2/comp/telecom/phone)

As soon as possible.

Aslund is a supported part of the SRT release structure, package name Aslund (no longer aslund). It is built as any other package 'gmake Aslund.all' and is run via the workdir package (as is bbsim) via the asrun script; see the README files in the Aslund and workdir packages for usage information (also accessible in the documentation area of the simulation web page).

An associator is a Beta Operator that performs the operation of association. It is often useful to associate one candidate with another during analysis. Reconstruction candidates are associated with their appropriate Monte Carlo truth candidates, etc.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/beta2/beta2.html#associators)

The person who writes something.

Refers to physics involving fully reconstructed B candidates, both B+ and B0. There is a software package, BRecoUser, associated with this topic. The relevant analysis working group is the EHBDOC AWG.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Physics/Analysis/AWG/EHBDOC/EHBDOC.html)

The analysis procedures used to distinguish decays of b quarks from decays of anti-b quarks.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Physics/Tools/Tagging/Main/index.html)

anti B meson.

Major particle of study for the BaBar collaboration. Contains one bottom quark and either a up quark (charged-B) or a down quark (neutral-B). At the BaBar detector, the B-mesons are daughter particles of the Upsilon (4S) particle.

Neutral B meson composed from a quark d and an anti-quark b

B and B-bar experiment.

Reference Link (http://www.slac.stanford.edu/BFROOT)

c++ is the programming language adopted as the main one in the official BaBar code.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Computing/Programming/ProgC++class.html)

Babar Conference Room is P&E Bld (Bld 280), Rm 162 (12 people). Contact Kazuko Onaga, x4625 or Kathy Webb, x2363.

Reference Link (http://www.slac.stanford.edu/gen/pubinfo/slaconly.contact.html)

The reference link below points to a BaBar detector image gallery.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Detector/Images/Images.html)

This is an operations software tool used to interface with PEP-II. It is an EPICS application.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Detector/Operations/EPICS/cen-bip/http/bipMain.html)

The BABAR acronym, which is the name of the experiment and detector collaboration, refers to the B/B-bar system of mesons which are produced at SLAC's PEP-II collider. Babar and the distinctive likeness are trademarks of Nelvana and are used with permission. (TM & ? Nelvana, All rights reserved.)

Reference Link (http://www.slac.stanford.edu/BFROOT/BABAR.html)

BABAR Notes consist of technical and non-technical memos on all manner of subjects relevant to the BABAR Collaboration. Topics include physics at the PEP-II collider, detector design, simulation, collaboration issues, etc.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/attic/BaBarNotes.5feb99)

BaBar Object-Oriented Geant4-based Unified Simulation, (BOGUS), is the BaBar fast- and detailed-simulation layer over Geant4 running in the BaBar Framework.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/sim/sim.html#bogus)

The logbook (which for BaBar exists as a computer file) in which the physicists on shift keep track of the daily operations, ie status of beams and detector, data taken etc.

BaBar Analysis Document - Frequently updated internal Babar documents available to BaBar collaborators. BAD notes are generally an individual's or group's work in physics analysis, detector performance, analysis tool documentation, upcoming conference ta lks, or drafts of soon to be published papers.

Acronym for BaBar Analysis Documents

Reference Link (http://www.slac.stanford.edu/babar-internal/BAD/doc/index.html)

Unit of scattering cross section. This is the number of particles scattered into a solid angle per unit time and then divided by the incident intensity. 1 Barn equals 10^(-28) m^2.

Central portion of the BaBar detector. Contains, within the super-conducting magnet coil, the silicon vertex detector, the drift chamber, the DIRC (ring imaging Cherenkov detector), electromagnetic calorimter and cylindrical resistive plate chambers. This is all located inside the 18 layer of steel of the flux return. Between the layers of steel are currently located resistive plate chambers. (The link is to the Technical Design Report, which contains drawings of the parts of the detector.)

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/TDR/)

This is the specific I/O Board used in the barrel region of the EMC DAQ system. The EMC DAQ system uses a different I/O board in the end-cap region, see EIOC.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Detector/DAQ/Calorimeter/WriteUps/IOB.pdf)

A test release is based upon the a specific production release which is the base release.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/srt1/srt1.html#using_srt)

The fundamental unit of persistent data is a basic object.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/objectivity1/objectivity1.html#terms)

Interactive processing is intended for those activities that truly require user interaction, e.g. debugging, or are very short.Other jobs should be submitted by batch. This includes but is not limited to CPU intensive jobs. The batch utility reads comman ds to be executed at a later time. Batch jobs are usually submitted to a special queue, specifically for batch jobs. Batch jobs will be submitted to the batch queue for immediate execution.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/batch/batch.html)

anti B meson.

TCL control file for BetaApp which is used to read the micro level information into Beta application for analysis.

See "beam energy substituted mass"

The Bear application runs the full BaBar reconstruction chain, invoking the reconstruction modules within the SVT, DCH, DRC, EMC and IFR sub-systems. The output from Bear is designed to be used in physics analyses.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/reco/reco.html#bear)

A basic reconstruction output format based on RogueWave and used for MDC 1. Beast is now obsolete.

Detector at KEK-B storage rings for study of CP violation using B-mesons.

Reference Link (http://belle.kek.jp/)

Beta is an analysis toolkit for use with BaBar data. It forms the basic interface to the complete reconstruction of BaBar data. The primary goal of Beta is to provide a simple, common basis for writing detailed physics analysis programs.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/beta1/beta1.html)

An electronic system in the BaBar counting room which activates a siren in case of serious malfanctioning of the detector.

A Beta Candidate is a representation of what is known or assumed about a (alleged, thus candidate) particle. Candidates are represented by the BtaCandidate class, and contain the mass, momentum, geneology (mothers and daughters), vertex information, etc., for the hypothetical particle.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/beta1/beta1.html)

A Beta Candidate is a representation of what is known or assumed about an (alleged, thus candidate) particle. Candidates can represent various levels of processing, various data types: a reconstructed object, a combination of candidates, a transformation of a candidate for a few examples. Candidates are represented by the BtaCandidate class.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/beta1/beta1.html#candidates)

A Beta Operator can combine one or more Beta Candidates to form new ones. Vertexing, mass constrained fitting, and simple 4vector addition are all operators.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/beta2/beta2.html#operations)

Beta* is the value of the beta function (accelerator lattice function) at the interaction point. There are four different beta*'s, a horizontal and a vertical for each beam.

The betarun* script facilitates running the BetaApp executable.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/beta1/beta1.html)

A package providing a set of tools for use in Beta level analysis.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Physics/Tools/BetaTools/BetaTools.html)

BetaUser is a package that has been created to facilitate a user's interaction with the larger scale Beta package. The BetaUser package, which makes the BetaApp executable, is where individuals can develop their own analysis.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/beta1/beta1.html)

BFDIST is a UNIX environment variable that is set to point to the top of the directory tree containing production releases and packages. The default is $BFROOT/dist. SoftRelTools uses this variable to locate the production releases on which users base their test releases. It must contain two directories: packages and releases.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/srt1/srt1.html)

BFMAIL allows you to send email to centrally managed BaBar mailing lists.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/info_resources/info_resources.html#bfmail)

The bfreport command reports information from the PRV0 production database. Use it anytime you want to find the name of a collection of interest.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/find_data/find_data.html#bfreport)

BFROOT is a UNIX environment variable that is set to point to the top of the BaBar file system. Most references to the BaBar file system should be made through this environment variable. In this way users are protected from changes in the physical locati on of the disks.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/srt1/srt1.html)

The "BGFilter" is a software filter used in Prompt reconstruction. It is run after track reconstruction in the drift chamber and cluster finding in the calorimeter, but before full reconstruction. The filter is fully documented in BAD 194.

Reference Link (http://babar-hn.slac.stanford.edu:5090/babar-internal/BAD/doc/detail.html?docNum=194)

BGFMuMu is a tagbit used to identify events which pass the background filter (BGF) and are identified as dimuon (e+e- -> mu+mu-) events. These events are used primarily for calibration.

simulation executable built on the Geant4 toolkit which takes four-vectors from an event generator and propagates them through the detector, producing GHits. The detector geometry is also built in BgsApp.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Computing/Offline/Simulation/web/bogus-guide.html)

An event in which an electron and positron scatter from one another (Bhabha scattering). Such events are backgrounds in the BaBar detector and are used for calibration.

In bhabha scattering, an electron and positron annihilate to form a photon, which in turn creates another electron positron pair.

A binned likelihood fit is a fit to a binned distribution (histogram).

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Physics/Analysis/Statistics/Report/report.pdf)

A Unix command that returns the status of a users batch jobs.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/batch/batch.html#bjobs)

A Unix command for killing a batch job.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/batch/batch.html#delete)

Power loss to SLAC site. BaBar has procedures to deal with this (see link).

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Detector/Operations/CareAndFeeding/care/node135.html)

Please see Blind Analysis.

Reference Link (http://www.slac.stanford.edu/babar-internal/BAD/doc/download.html?file=00091.002.ps)

To boost a BtaCandidate from one frame to the other, you can use a BtaBooster, which comes from the BetaCoreTools package. The link gives additional information about accessing the machine boost and other beam parameters.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Physics/Tools/PepBeams/#access)

Creating a new federation generates a Boot File. The Boot File describes the federated database configuration, its own location and file server, the FDID, lock server node, and other parameters describing the federation. By BaBar convention this fil is named BaBar.BOOT.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/objectivity1/objectivity1.html#terms)

A Unix command to peek at the output of a batch job in progress.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/batch/batch.html#output)

A Unix command that returns a list of available batch queues.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/batch/batch.html)

Radiation is emitted when charged particles are accelerated. When a charged particle passes through the field of atomic nuclei, it emits radiation and loses energy in the process (Bremsstrahlung is German for decelerating-radiation)

When power available to SLAC is reduced because of grid production limits, the site undergoes a brown out where large electrical power loads (eg, accelerator, BaBar systems) are shed. BaBar has procedures for this situation (see link).

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Detector/Operations/CareAndFeeding/care/node135.html)

When power available to SLAC is reduced because of grid production limits, the site undergoes a brown out where large electrical power loads (eg, accelerator, BaBar systems) are shed. BaBar has procedures for this situation (see link).

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Detector/Operations/CareAndFeeding/care/node135.html)

A day during a period of data taking in which the accelerator operations are stopped, due to a high demand for electrical power - typically from many air conditioners on in hot summer days - from the SLAC power provider.

A Unix command to command to submit batch jobs.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/batch/batch.html#bsub)

A BtaCandidate is a Beta level representation of a possible particle candidate. The workbook has more details.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/beta1/beta1.html#basics)

Skim defined by SemiLeptonic Analysis Working Group. It contains B -> D(*)(*) l nu events

Reference Link (http://www.slac.stanford.edu/~jack/recoil/dlnuskim.html)

A buffer is used to help eliminate latency is a system by having a number of transactions being able to occur without waiting of something else keeping up.

Many builds are done of the BaBar software. There are various kinds, online, offline, dataflow, physics, lettered and probably some others. Most of these will end up under $BFDIST.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Computing/Offline/SoftwareAdmin/SoftwareAdmin.html)

Group of crystals in the calorimeter (EMC) where a particle has deposited some energy.

The program the accelerator operators use to control injection. It shakes hands with the BISM.

This EPICS function manages the interaction between BaBar and PEPII from the BaBar side.

An object-oriented compiled language, formally standardized in 1998, with an heritage from C.

Reference Link (http://www.cplusplus.com/)

A list of neutral Beta Candidates with EMC showers not matched to any charged track

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Detector/Calorimeter/software/index.html)

CAMAC modules in the power supply alcove (building 624), rack 5, that trigger beam aborts if the DCH and EMC PIN diodes read values above their respective thresholds.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Detector/Backgrounds/liaisons/CBAM.html)

A data bus used by Detector Controls to obtain monitoring data, such as temperatures and voltages. See BaBar Notes 365 and 366.

List of reconstructed "candidate" particles. This term is used in the Beta analysis program package

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Computing/Offline/Beta/Beta.html)

This is a manual that attempts to put in one place all the directions for how to keep the BaBar detectors, electronics, and computers running. It is stored in the BaBar CVS repositor as the project CareAndFeeding.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Detector/Operations/CareAndFeeding/care/care.html)

The "Care and Feeding of BaBar" (aka "The Care Manual") attempts to put in one place all the directions for how to keep the BaBar detectors, electronics, and computers running. It is stored in the BaBar CVS repository as the project CareAndFeeding.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Detector/Operations/CareAndFeeding/care/care.html)

CEN-BIP is an Input/Output Controller (IOC) running the VxWorks operating system and EPICS software. Its named for its main purpose which is to manage the BaBar injection. It communicates via a private network with CEN-BIC, an IOC at Main Control Center (MCC) accepting the injection after notifying the BaBar subdetectors to ramp down and getting confirmation back that all are safe. CEN-BIP denies the PEP injection if it doesn't receive the all-safe confirmation from the subdetectors. Once the injection is complete, CEN-BIP instructs the subdetectors to ramp-up to High Voltage. CEN-BIP does some other tasks as well. For eg, it keeps track of luminosity, integrating instantaneous values which are written to oracle database. It also communicates with Run Control (ORC) to inform ORC re: health of the detector and data acquistion status.

CERNLIB is a set of software libraries and programs to aid in the development of High Energy Physics applications. It includes function libraries (kernlib, mathlib, packlib etc.), histogramming facilities (HBOOK, HPLOT), the analysis tool Paw and th e simulation toolkit Geant3.

Reference Link (http://www.slac.stanford.edu/comp/physics/cernlib/cernlib.html)

A popular component of photon detectors.

A method used by EPICS applications for collecting data from monitoring VME crates. See EPICS.

B refers to B meson, charged is either electrically positive or negative, ie B+ or B-, the quark wave function of B+ is (bbar u), u is the u quark, bbar the anti b quark.

Decays of the B meson are classified according to the quark content of the final state. If there are no charm quarks c in the final state, we speak of charmless B decays. There are many examples of charmless B decays, some of them are B -> pi pi, B -> K K, B -> pi K, B -> rho rho, B -> rho K*, B -> phi K*.

Citrix is the Windows Terminal Server used at SLAC. This allows you to use windows applications from Solaris or Linux machines (or even any X-Windows terminal by running the citrix application on Solaris or Linux).

Reference Link (http://www2.slac.stanford.edu/comp/winnt/wts/citrix_at_slac.html)

A Class Library for High Energy Physics. CLHEP is part of Anaphe (ANAlysis for PHysics Experiments) which was formerly known as LHC++. Anaphe replaces CERNLIB and is written and maintained by CERN.

Reference Link (http://wwwinfo.cern.ch/asd/lhc++/clhep/)

A mult-threaded, cobra server used in Event Reconstruction to pre-create and pre-size databases and containers

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Public/Computing/Databases/experts/administering.shtml)

A mult-threaded, cobra server used in Event Reconstruction to pre-create and pre-size databases and containers

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Public/Computing/Databases/experts/administering.shtml)

Software that collects the error messages generated in various parts of the BaBar online system and displays them centrally.

Periodic meetings of collaborators to 1. discuss detector performance, provide a forum for short term planning of detector operations, 2. review and plan detector upgrades, 3. provide a forum to critique and improve physics analysis in preparation for conference presentations and journal articles, 4. provide an opportunity to present reports from task forces, workshops, etc.

An event collection contains references to events within the Event Store.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/objectivity1/objectivity1.html#collections)

Collection names are the mechanism by which collections are accessed from the BdbEventStore object.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/objectivity1/objectivity1.html)

Typically refering to background resulting from random combinations of charged and/or neutral particle candidates. May also refer to signal candidates which are composed of a decay in which one or more of the true daughters have been replaced by a rando m track or photon from the rest of the event.

The process of bringing a newly constructed detector into routine operation.

'Commit' is a VCS (Concurrent Version System) command that means 'commit your changes". Use this command when you wish to 'publish' your changes to other developers, by incorporating them in the source repository.

Reference Link (http://sunsite.ualberta.ca/Documentation/Gnu/cvs-1.11.1p1/html_node/cvs_6.html#SEC6)

The new BaBar computing model.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Computing/Documentation/CM2/intro/)

The committee has two functions. Firstly, steering the contributions of the Tier-A centers. Then advising the International Finance Committee on the financial value of these contributions and the size and cost of total BaBar Tier-A requirements. Secondly, advising BaBar management on computing issues affecting remote collaborators.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Computing/CSC.html)

The Conditions Database is a repository for history under which data was acquired or processed. This includes geometry, electronics calibrations, detector alignments, trigger/online/detector configuration, and recontruction adjustable parameters. The Con ditions Database is designed to allow for a complete description of the detector as a function of time, where different components of the detector may exhibit different time variances.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/objectivity1/objectivity1.html#condDb)

A component of the Babar on-line database, which includes the subdetector information.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Computing/Online/Databases/OnlineDatabases.html)

Data which is indexed by the configuration key. The map of crates in the partition is an example.

The structure in the control room at which the experiment is monitored and run.

Each persistent object is created in an Objectivity database and is stored in a container. One or more containers compose a database.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/objectivity1/objectivity1.html#terms)

Non-resonant production of primordial u u(bar), d d(bar), s s(bar) and c c(bar) quark pairs in e+e- annihilations.

The room with the console and other workstations for running the BaBar detector. The control room is located in IR2.

Standard for a serial bus used for instrumentation and control.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Computing/Online/Detector/hardware/CAN_Micro.html)

Standard for a serial bus used for instrumentation and control.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Computing/Online/Detector/hardware/CAN_Micro.html)

There are two versions of this object, BdbConversionManager and RooConversionManager, these are used to manage the input and output of data between the persistent events stores (BaBar Datastore and Kanga) and the transient job.

Tagging in BaBar is done using the Cornelius++ package. Actually, Cornelius++ is a rather general tool and can do more than just tagging. For each event, Cornelius++ can provide: the relative probability, that the tagging B was a B0 (or B0 bar), the list of particle(s) used to tag the B.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/analysis/analysis.html#tagging)

A commercial electronics supplier. Many BaBar high voltage power supplies are from CAEN.

Reference Link (http://www.caen.it/)

Building 621 which is attached to the IR2 hall (building 620). The first floor of the counting house houses the Control Room and the Cornelius conference room. The second floor houses the rest rooms, the kitchen, and the maintenance area.

CP transformation: combination of charge conjugation (C: particle-antiparticle exchange) and parity transformation (P: space reflection)

Reference Link (http://www.slac.stanford.edu/pubs/confproc/babar504/babar504-001.html)

Phase difference between combinations of CKM matrix elements in the so-called triangular unitarity relations. See for instance BaBar Physics Book, Section 1.4.2, p.19

Reference Link (http://www.slac.stanford.edu/cgi-wrap/getdoc/babar504-001.pdf)

Violation of the symmetry for CP transformations.

Reference Link (http://www.slac.stanford.edu/pubs/confproc/babar504/babar504-001.html)

The cross section is a representation of the quantum mechanical probability that a particular fundamental interaction will occur when a projected particle gets within an effective transverse area centered on the target particle. The cross section can be viewed as the effective area that a target presents to a projected particle.

Reference Link (http://www-ed.fnal.gov/painless/htmls/cross.html)

current is a symbolic link to the most recent release to have reached an acceptable level of quality. Acceptable is detemined by a combination of code and physics checks as defined by the QA/QC group with input from the physics groups and detector subgoups. The QA/QC coordinator determines which release this should point to.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/srt1/srt1.html)

Part of the EMC electronics.

Also "CX" (preferred). Historic name of a bfmail mailing list. Now refers to the BaBar computing management group.

In track helix parameterization the distance of closest approach to the origin of coordinates. This quantity is signed in such a way that |1/k + d0| is the distance between the origin of coodinates and the helix center in the x-y plane. (k is the pro perly signed helix curvature).

Digital to Analog Converter

A Dalitz plot is a way to represent the entire phase space, viz, all essential kinematical variables, of any three-body final state in a two-dimensional histogram.

Reference Link (http://rd11.web.cern.ch/RD11/rkb/PH14pp/node39.html)

Objectivity requires the use of C++ classes that are defined in Data Definition Language, (DDL), files. DDL files have a name with a .ddl suffix.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/objectivity1/objectivity1.html#terms)

The name given to moving data between sites.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Computing/Offline/DataDist/)

Component of Drift Chamber front-end electronics. Multiplexes data and commands between fiber-optic link to Readout Module (ROM) and 12 front-end assemblies (FEAs) in one quadrant.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Detector/CentralTracker/electronics/doc/dc_elec_diom.ps.gz)

Sets environment variable OO_FD_BOOT to specify what data will be used, also see mc12boot, cond14boot, etc.

Sets environment variable OO_FD_BOOT to specify what data will be used, also see mc12boot, cond14boot, etc.

A database is where an application's persistent data is stored. A database is physically represented by a database file, which is made up of all containers and basic objects stored in the database.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/objectivity1/objectivity1.html#terms)

Each database is identified both by its file system location and by a unique Database ID, (DBID), number.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/objectivity1/objectivity1.html#terms)

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Computing/Online/DataFlow/OnlineDataFlow.html)

The debugger, dbx, is available on all BaBar platforms.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/debug/debug.html)

A debugger is a tool that allows one to trace problems in a program at the source code level. A debugger enables you to control a program's execution, symbolically monitor program control, flow, variables, and memory locations.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/debug/debug.html)

A developer database is a federation that becomes part of the user's private test release environment. It is copied from the reference database associated with the base software release. A developer database contains a default copy of the condition data, and is otherwise initially empty (the Event Store contains no data).

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/objectivity1/objectivity1.html#types)

The smallest data element provided by the DAQ. It corresponds to one hit.

Representation in the reconstruction of a single readout channel. E.g. a DchDigi corresponds to one hit wire.

the combination of detector signals from a real background event and a simulated physics event to form a realistic simulated event; performed in SimApp by overlaying background and physics digitizations.

Dip angle is the angle between the track momentum and the x-y plane.

In track helix parameterization, the polar angle between the z-axis and the track momentum.

Direct CP violation: The decay rate B -> f is different form the decay rate for Bbar -> fbar. Direct CP violation has been observed in the Kaon system and recently also in the B meson system. In order for direct CP violation (=CP violation in decay) to occur 3 conditions must be met: (1) more than 1 amplitude for single decay (2) weak phase difference between amplitudes not equal to 0 (3) strong phase difference between amplitudes not equal to 0

Distance of closest approach a) of a track to a reference point or line, e.g., the z-axis passing through the coordinate origin, or through the beam spot center, or to a vertex. b) of a track to a sense wire in the Dch.

The Distributed Histogramming Package (DHP) provides a means of collecting histograms simultaneously across multiple nodes of the online farm, viewing them while the run is still in progress, and collecting and storing them at the end of the run.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Computing/Online/EventProc/jas/1999-05-19-Forum-JAS/online-dhp.html)

System for accumulating histograms in processes distributed across a farm of computers, while providing a single view of the full statistics to clients. Used in BaBar to accumulate data quality monitoring histograms in the OEP / Level 3 processes in the online system. Implemented as an application of the BaBar Distributed Object Tree (DOT) software.

client-server system that provides a general framework for publishing a set of strongly-typed information from a distributed collection of processes, with a means for obtaining a unified view of all the information from a client. A type-specific "merge" operation can be defined that will be used by the framework to combine information from multiple sources. Typically this operation might be to sum or average contributions from the sources.

A type of tape storage medium. DLT-IV has a storage capacity of 35 Gb uncompressed.

Please see DOCA

DRC is the three letter acronym, (TLA), for the Detector of Internally Reflected Cherenkov radiation, which is more commonly abbreviated as DIRC.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/detector/detector.html)

The second component of the BaBar tracking system is the drift chamber, (DCH). It is used primarily to achieve excellent momentum resolution and pattern recognition for charged particles with p_t > 100 MeV/c.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/detector/detector.html#systems)

This is the charged particle trigger of the detector's Level 1 trigger system.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Detector/Trigger/trigger_whatsit.html)

Ds meson (quark content c-sbar) with spin J.

City in Italy where BaBar collaboration meetings are held from time to time.

The BaBar electromagnetic calorimeter, (EMC), is a fully projective CsI(TI) crystal calorimeter.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/detector/detector.html#systems)

This is the neutral partical trigger of the detector's Level 1 trigger system.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Detector/Trigger/trigger_whatsit.html)

An energy deposition in the Babar EMC by either a photon or an electron is one example of an electromagnetic shower. When a high-energy photon passes near a heavy nucleus (Cs or I in the EMC), it can convert into an electron-positron pair. Similarly, a high-energy electron passing near the nuclues can radiate a photon. Either of these events leads to a rapid chain reaction, with one high-energy particle giving rise to many low-energy photons, which are measured by the EMC.

The building on the IR2 hall floor which houses the off-detector electronics. There are electronics on the first level and electronics and utilities on the roof.

Elf is a package of the BaBar SRT . It is for integrating Bear and Online Prompt Reconstruction (OPR). Look at the README file in the package for more information.

Elf is a package in the BaBar software repository. Elf is a package for integrating Bear and online Prompt Reconstruction. Check out the head version of the package for any documentation.

This is the specific I/O board used in the end-cap region of the EMC DAQ system. There is another I/O board used in the barrel region of the EMC DAQ, see BIOB.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Detector/DAQ/Calorimeter/WriteUps/IOB.pdf)

The person in charge of the crew on shift in MCC.

In UNIX, environment variables are accessible to programs that you run as well as to the shell from which you work. By convention, their names are all upper case. Environment variables may be set and unset directly by the user at the prompt, or through scripts, applications, and so forth.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/unix/unix.html)

In the context of the database, an event is a heirarchy of all the stages in its processing. It is represented by an event header which contains references to the multiple child objects, each corresponding to a particular stage in the processing.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/objectivity1/objectivity1.html)

Event shape variables are used to separate mostly isotropic B-B(bar) events from jet-like q-q(bar) events. An introduction to the subject can be found in the BaBar Physics Book, Section 4.9, p.181

Reference Link (http://www.slac.stanford.edu/cgi-wrap/getdoc/babar504-004.pdf)

The Event Store manages and tracks the experimental data from the initial raw data produced either by experiment or simulation through various reconstruction and physics analysis processing phases. It also provides a mechanism for creating specific sets of events.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/objectivity1/objectivity1.html)

EvtGen is a generator of Upsilon(4S)and qqbar events.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/gen/gen.html#xx)

Refering to fully reconstructed decays of a specific type. To be contrasted with inclusive, which refers to classes of fully or partially reconstructed decays.

As defined in the BABAR Collaboration Governance Rules: "The Executive Board is responsible for advising the Spokesperson on all scientific financial and organization matters pertaining to the Collaboration." Membership includes one elected representative each from Canada, France, Italy, Germany. There are five US representatives to the Executive Board, one from SLAC, one From LBNL, and three from the universities and LLNL. The Spokesperson and Technical Coordinator are ex-officio members of the Executive Board. The current membership is listed at:

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Organization/ExecBd/)

A group which supports experimenters at SLAC. It is part of the Research Division. The cryogenics group is part of EFD.

This is the basic binary format for BaBar raw data. It provides a compromise between standard C++ object semantics and a more traditional "pointer-and-length" C-style way of working with bulk binary data. An XTC object is basically a variable-length piece of data with a header that specifies its type and size. The term "XTC" is used in two ways in BaBar. It can be used to refer to a single increment of raw data or its data type: e.g., "the XTC from the GLT ROM", or "the SVT XTC format". I

A machine-independent data representation is achieved through a set of translations based on the eXternal Data Representation, (XDR), Networking package. This file output format, xdr files, are the standard output of bbsim.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/xdr/xdr.html)

Event simulation which is significantly faster (~100 - 1000 times) than a detailed simulation. The increased speed is usually achieved at the expense of detector detail or the amount of hit information stored per event.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Computing/Offline/Simulation/web/simcodes/fastsim/fastsim_main.html)

An algorithm which determines the quantities of interest from raw detector data; e.g. a routine that calculates hit time and energy.

A federation is physically represented by a Federated Database File. By BaBar convention the file is named BaBar.FDDB

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/objectivity1/objectivity1.html#terms)

Each federation is identified by a unique Federated Database ID, (FDID), number.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/objectivity1/objectivity1.html#terms)

A set of related database files and objects that can be accessed by a single application is called a federation or federated database. This is a higher level structure than a database.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/objectivity1/objectivity1.html#terms)

Unit of cross-section. (1 barn = 10^-28m^2).

A fermion is any particle that has half-integer spin i.e. 1/2. 3/2, 5/2 ...
All leptons and quarks are fermions.
Fermions are so called because they obey Fermi-Dirac statistics - named for physicists Enrico Fermi and Paul Dirac.
Fermions are subject to the Pauli exclusion priciple, preventing identical fermions from having identical quantum numbers.

Reference Link (http://www2.slac.stanford.edu/vvc/theory/spin.html)

Detector coverage based on some quality requirements.

Grounded wire in drift chamber. Six field wires surround each sense wire, and shape the electric field in the cell.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Detector/CentralTracker/mechanical/drift_system/index.html)

This type of module can terminate or re-direct the subsequent processing of an event based on its filter criteria and the characteristics of an event.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/framework1/framework1.html)

A basic operation of analysis is creating acceptable candidates for a particular reaction from scratch. For example, K0 candidates can be made by vertexing pairs of pion candidates, vertexing, and applying cuts. To the extent that these are reusable in o ther analyses, they become finders. All the finders take as input one or more lists of BtaCandidates and return a list of the objects they were meant to look for.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/beta2/beta2.html#finders)

Linux and UNIX command for user information lookup

Reference Link (http://www.slac.stanford.edu/comp/unix/unix-guide/chap8.frame.html)

Low-level software that is run on programmable electronics; e.g. FPGA. Not as rigid as hardware; not as mutable as software.

In a particle physics context, a Fisher Discriminant is a linear combination of some set of measurements. The coefficients of the Fisher Discriminant are determined in a standard way which maximizes its overall ability to discriminate between signal and background events.

In a B Factory context, the set of measurements used in a Fisher Discriminant usually includes various event shape variables, such as the angles between candidate particles, the energy flow within each of nine cones, and the ratio of the second and zeroth Fox-Wolfram moments.

Reference: Fisher, R. A., Annals of Eugenics 7, 179 (1936)

Reference Link (http://www.library.adelaide.edu.au/digitised/fisher/138.pdf)

A fitter is a Beta operator. Given a tree of BtaCandidates it performs a fit to the whole tree interpretingall the constraints (geometric+kinematic), returning a modified version of the tree with improved vertices and momenta.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/analysis/analysis.html#vertexing)

Electronic device which converts a voltage into a number in one step. Used in the DCH front end electronics and elsewhere.

A fire suppresent gas. It is an ozone friendly HALON substitute. FM2000 is heptafluoropropane, also known as HFC-27ea.

Two real meanings related to computing. You can format a device to remove all data on it and lay it out for use by the OS. You could also talk about a file format (the layout of data within it). (A third is the fortran FORMAT command which defines the layout of a WRITE output.)

A series of meetings regarding BaBar physics, reconstruction, and simulation.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Physics/Forum/forum.html)

Fox Wolfram moments (FW(l) of order l = 0, 1, 2 ..) are defined as : Sum_ij |p_i| |p_j| P_l (cos theta_ij), where the summation is over all final state particles, p_i and p_j are momenta of the particles i and j, theta_ij is the angle between them and P_l are the Legendre polynomials of order l : P_0(x) = 1, P_1(x) = x, P_2(x) = (1/2)(3x^2-1), P_3(x) = (1/2)(5x^3-3x), P_4(x) = (1/8)(35x^4-30x^2+3), P_5(x) = (1/8)(63x^5-70x^3+15x), P_6(x) = (1/16)(231x^6-315x^4+105x^2-5), ...

In the context of a HEP experiment such as BaBar, the framework is a system that allows physicist developed code to be combined with code developed by others to perform analysis. The framework is implemented by the Framework package.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/framework1/framework1.html)

The system electronics responsible for amplifying, digitizing, and selecting time slices from the detector signals.

A temporary data storage area in the on-detector electronics where event data is stored until it can be transmitted to the data acquisition readout modules.

A unit of measure of worker effort. If two people work on a job full time then that is 2 FTEs, if they both work half time then it is only 1 FTE.

Forward end of detector (south end); incoming beam is LER (e+)

The building next to the utility pad and the ring in which the DCH and IFR gases are prepared.

The common electronics interface board where detector monitoring/control signals are converted to/from signals on CANbus. This is the BaBar hardware interface to EPICs.

Reference Link (http://www.slac.stanford.edu/~wtmeyer/detcon/gmb/gmb.html)

The Generator Framework Interface, (GenFwkIn), is used to generate events in the Babar Framework using various underlying generators.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/gen/gen.html)

BaBar software package for vertex fitting with geometric and kinematical constraints

Reference Link (http://www.slac.stanford.edu/babar-internal/BAD/doc/detail.html?docNum=102)

primitive hit information such as a particle's location and energy at a detector boundary, generated by a tracking and physics simulation module such as BgsApp, persisted in the database, and transmitted to a detector simulation module such as SimApp.

The work required to move a charge of one electron through a potential difference of one billion volts.

The GLT attempts to match the angular locations of calorimeter towers and drift chamber tracks, and flexibly generates Level 1 triggers and sends them on to the Fast Control and Timing system (FCTS), based on the results of the processing.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Detector/Trigger/trigger_whatsit.html)

A GNU make tool. Make is a tool which controls the generation of executables and other non-source files of a program from the program's source files.

Reference Link (http://www.gnu.ai.mit.edu/software/make/make.html)

In Beta, a general class of track selectors. This term is normally qualified with the level of selection, e.g., GoodTtracksVeryLoose and in this context refers to a list of tracks in a BaBar event.

Charged tracks having a minimum transverse momentum of 0.1 GeV, at least 12 hits in the drift chamber, and which pass within 10 cm of the beamspot in z and 1.5 cm from the beamspot in x-y.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/nanomicro/v8.8/Micro/CandLists.html)

a type of BABAR track list, defined in BetaMicro/BtaGoodTrkSelector.cc

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/nanomicro/v8.6/Micro/Cand_Lists.html)

Name given to automatic data and computational distribution to globally spread resources. BaBar has a group working on utilising this technology.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Computing/Offline/BaBarGrid/)

grl selector is the name for a proton selector that was implemented by Margaret Haire. It is based on a method developed by Gerry Lynch. Items 43,49, and 87 in the "Hadron ID AWG" hypernews describe the method and the selector.

Device used to detect flammable gas mixtures.

The group at SLAC responsible for heating and cooling. Among other tasks, they maintain the water plant on the IR2 utility pad.

Class in CLHEP library representing a real-valued 3 dimensional vector.

Reference Link (http://babar-hn.slac.stanford.edu:5090/cgi-bin/internal/cvsweb.cgi/CLHEP/Vector/ThreeVector.h)

This class is a part of CLHEP - a Class Library for High Energy Physics. Hep3Vector is a general 3-vector class defining vectors in three dimensions using HepDouble components. Rotations of these vectors are performed by multiplying with an object of the HepRotation class. More information about structure of the class can be found in any release distribution in file CLHEP/Vector/ThreeVector.h. For release analisys-12a the full path is /afs/slac.stanford.edu/g/babar/dist/releases/analysis-12

Lists, specifically HepALists, of BtaCandidates are stored within an event (type AbsEvent). Possible lists in an event may be of charged tracks or of muon candidates.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/beta1/beta1.html)

The High Energy Physics Information Center, better known as HEPIC, is an information server that catalogs various HEP Resources throughout the world. HEPIC exists, to aid the HEP Researcher in locating information quickly and efficiently. HEPIC can be found at www.hep.net, and is supported by the Fermilab Computing Division. It provides information ranging from Events (Conferences, Schools, Workshops), Experiments, General Phonebooks etc.

Reference Link (http://www.hep.net)

HepLorentzVector is a class in CLHEP lib. It is a Lorentz vector consisting of Hep3Vector and double components. Lorentz transformations (rotations and boosts) of these vectors are perfomed by multiplying with objects of the HepLorentzRotation class.

C++ class of objects in CLHEP library, representing 4-vectors and all the operations and transformations applicable to them.

Reference Link (http://wwwasd.web.cern.ch/wwwasd/lhc++/clhep/manual/RefGuide/Vector/include/LorentzVector_h.html)

Class in CLHEP/Vector representing 4-vectors.

Plastic comb structures with wires strung between the teeth of the comb structure.A plastic cover plate forms the 4th surface of the tube. The surface of the comb structure is coated with a graphite bearing paint. The wire is held at high voltage. Limited streamers are produced when charged particles interact in the gas of contained in the comb structure. Pickup electrodes are located outside the plastic structure.(Also known at Limited Streamer Tubes (LST).) Technology chosen by BaBar for upgrade of the Instrumented Flux Return (barrel section).

Reference Link (http://ccdb3fs.kek.jp/cgi-bin/img/allpdf?197704192)

The set of activities performed for the Instrumented Flux Return detector subsytems maintenance

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Detector/IFR/IFR.html)

Inclusive Hadronic B Decays analysis working group

Reference Link (http://BFROOT/www/Physics/Analysis/AWG/IHBDecays/IHBDecays.html)

Inclusive Hadronic Particle Spectra Analysis Working Group

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Physics/Analysis/AWG/ihaps/)

This type of module acts as the source of data. There will be a module to read from the online system or event generators. Only one input module may be active in a path at any one time.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/framework1/framework1.html)

The basic computational module of the BaBar online detector control system. At present (April 2002) the IOCs in use are Motorola MV177 (Power PC based) cards for use in VME crates. These run the VxWorks real time operating system.

Reference Link (http://www.vme.ru/pdf/MVME177.pdf)

The basic EPICS data gathering processor. In our case they are all Motorola MVME 177 SBCs. (Part of the control system of PEP-II.)

I/O Boards are used in BaBaR Detector DAQ systems. The EMC DAQ uses two different types of I/O Boards, see BIOB and EIOB.

Input/Output Controller (IOC), for BaBar, refers to a VME crate running VxWorks, usually on an mv177 CPU with other controller boards installed for the purpose of controlling instrumentation and hardware. The other boards used at BaBar are, for eg., CAEN controllers, VSAM (VxWorks Smart Analog Module), SIAM, CANbus, GPIB, etc. At BaBar, there are 17 IOCs used as part of the Online Detector Controls.

The BaBar Instrumented Flux Return, (IFR), is designed to identify muons with minimum momentum around 0.5GeV/c and to detect neutral hadrons.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/detector/detector.html#systems)

This is the cosmic particle trigger of the detector's Level 1 trigger system.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Detector/Trigger/trigger_whatsit.html)

The point of interaction between two particles. In BaBar this is the interaction point between a beam of positrons and a beam of electrons. The IP of study in BaBar is within the detector at IR2.

The PEPII interaction region in which BaBar is located.

This committee represents the funding agencies that support BaBar. It is chaired by the SLAC Director of Research.

Instantaneous luminosity is measured usually in cm^-2s^-1. Integrated luminosity is a measure of the total luminosity and is thus measured in cm^-2. It is useful to use inverse barns (1 barn = 10^-28m^2) to express this. It then becomes easy using the cr oss-section for a particular interaction to predict the number of such events expected.

Instantaneous luminosity is measured usually in cm^-2s^-1. Integrated luminosity is a measure of the total luminosity and is thus measured in cm^-2. It is useful to use inverse barns (1 barn = 10^-28m^2) to express this. It then becomes easy using the cr oss-section for a particular interaction to predict the number of such events expected.

This is a Babar online environment defined command. Its main purpose is to set the OO_FD_BOOT environment variable to point to the IR2 production data base with the name of ir2boot. Do not use this command if you are not sure what you are doing. Acces ses to ir2boot from outside IR2 are blocked - and inside the IR2 environment they may leave locks affecting our ability to take data.

National Institute of Nuclear Physics. The main Italian institution in the field of Nuclear and High Energy Physics.

Reference Link (http://www.infn.it)

A job is an entire framework session.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/framework1/framework1.html#job)

A sequential linear least-squares algorithm which uses an initial estimate and incremental data to find an optimal solution. A variant of this algorithm is used as the mathematical foundation of the BaBar track fit. Code implementing the track f it is in package KalmanTrack.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Computing/Offline/Reconstruction/Tracking/trackDocu.html)

Kerberos is a network authentication protocol for client-server applications. It has been developed at MIT and uses secret-key cryptography to avoid transmission of cleartext passwords over the network. Kerberos is the authentication protocol used in AFS .

Reference Link (http://web.mit.edu/kerberos/www)

A kinematic fitter is a Beta operator. Given a tree of BtaCandidates with a set of kinematic constraints, it returns the best fit to the momenta/masses/energies of the candidates.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/analysis/analysis.html#vertexing)

Vertexing/kinematic fitting is a mathematical procedure in which one uses physical constraints governing a particle interaction or decay to improve the measurements describing the process. Explicit formulations of these constraints are based on geometric intersections, mass, energy, momentum, etc.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/analysis/analysis.html#vertexing)

A kink is a type of vertex with one charged track going in and one charged track going out. Examples are K -> mu+numu, K -> pi+pi0, and pi -> mu+numu, as well as bremsstrahlung, elastic scatter, and inelastic scatter processes with this topology.

Reference Link (http://babar-hn.slac.stanford.edu:5090/HyperNews/get/recoTracking/123.html)

A thermal fuse. A klixon is a temperature activated switch used to protect of machine components from overheating.

KoralB is a generator of tau-pairs.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/gen/gen.html#xxx)

Kumac is the language used to write PAW macros.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/paw/paw.html#macros)

ladebug is a GUI debugger available on OSF platforms.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/debug/debug.html#gui)

latest is a symbolic link to the most recently built release. The only quality requirement is that the release (mostly) compiled. The release coordinator determines which release this should point to.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/srt1/srt1.html)

LaTeX is a typesetting program, ideal for the preparation of scientific and technical documents.

Reference Link (http://www.latex-project.org/latex3.html)

A class of elementary particles that includes the electron and its antiparticle, the muon and its antiparticle, the tau and its antiparticle, and the neutrino and antineutrino associated with each of these particles.

A lepton is a fundamental particle of which the most common example is the electron ( e^- ).
The other leptons are the muon ( μ^- ), tau ( τ^- ), and three neutrinos ( ν_e , ν_μ and ν_τ ).
Electrons, muons and tau have a charge of -1, and neutrinos have charge zero.
Each lepton has an antimatter equivalent which has the opposite charge - for the electron, the antimatter equivalent is called the positron ( e⁺ ).
All leptons have a spin of one half, and are fermions.

Reference Link (http://www2.slac.stanford.edu/vvc/theory/leptons.html)

Shorthand notation for Level-1 Trigger. This is the first stage where events observed by the BaBar dectector are flagged as being interesting enough to keep for further physics analysis. In the case of the Level-1 Trigger, this decision is made by hardwa re.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Detector/Trigger/)

Shorthand notation for Level-3 software trigger. This applies further requirements through software to the events selected by the L1 trigger before they are stored.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Detector/Trigger/Level3/)

LHC++ is now called Anaphe, see there.

Reference Link (http://anaphe.web.cern.ch/anaphe/)

BaBar shifter who is posted in the MCC control room. This person provides communications between the Babar shift leader (pilot) and PEP operators and is particularly responsible for machine-detector interfaces for the shift.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Detector/Operations/shifts/shift_page_template.htm)

A calibration performed for the Electro-Magnetic Calorimeter (EMC) as part of the daily global calibration. Optic fibers carry light from a Xenon lamp to the back of the crystals while the data acquisition records the response of the system.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Detector/Calorimeter/Operations/EMC_LightPulser/index.html)

The likelihood method is a parametrized tagging method. It is denoted by the string PA in the code.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/analysis/analysis.html#tagging)

The LST system is the Babar IFR barrel upgrade, replacing resistive-plate chambers (RPCs) with limited-streamer tube technology.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Detector/LST/index.html)

A type of particle accelerator in which charged particles are accelerated in a straight line, either by a steady electrical field or by means of radio frequency electric fields.

Reference Link (http://www.slac.stanford.edu/)

The lock server is a process running on a designated computer that manages concurrent access to a database. No data passes through the lock server, but it ensures that data within the federation is consistent and prevents simultaneous updates from multip le clients.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/objectivity1/objectivity1.html)

A program that is used for event collection and distribution in BaBar online data acquisition and offline reconstruction. It collects data from the online farm (L3 nodes) and writes to an XTC file. It reads XTC files and distributes events to the offline reconstruction farm.

A name which is used to uniquely identify a file, without actually being the (physical) name of the file. In BaBar we use these to provide a site-independent name for files in the eventstore.

(p0, p1, p2, p3) with metric (1,-1,-1,-1). Also known as a four-vector.

The boost of the center-of-mass frame in the lab frame. The direction of the boost is measured run-by-run from 2-track events. The magnitude of the boost is taken from the measured PEP-II beam energies. The energies and the boost direction are stored in the conditions database.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Physics/Tools/PepBeams/)

Generic term for matters where the accelerator and the detector are interrelated. Often used in a context of background remediation.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Detector/Backgrounds/MDI_MTG/nextmeeting.html)

Mail stop is the mail delivery destination in SLAC. Mail stop numbers are used to identify the delivery point, such as ROB Bld 1st Fl(M/S 34); 2nd Fl, (M/S 35); Bld 280 (M/S 41).

The control room for the LINAC and PEP-II.

The primary 470MHz accelerator clock. Timing signals are derived from this clock.

mathlib is part of CERNLIB.

Reference Link (http://www.slac.stanford.edu/comp/physics/cernlib/cernlib.html)

Users who need samples of MonteCarlo events in BaBar can submit their requests to the Simulation Production (SP) system by using a web interface. The requests are then managed and assigned to production sites by using a relational database.

Reference Link (http://www.slac.stanford.edu/babar-internal/spreq/requests.html)

The work required to move a charge of one electron through a potential difference of one million volts.

Unit of energy. 1 MeV = 10^6 electron-Volts.

Reference Link (http://hyperphysics.phy-astr.gsu.edu/hbase/electric/ev.html)

This expresses a legal arrangement between (at least) two bodies.

A meson is a particle composed of a quark and an anti-quark.
Examples include π⁺ (composed of an up quark and an anti-down anti-quark) and K^- (strange, anti-up).
BaBar studies the properties of B mesons, such as B⁺ (u, anti-b), and B⁰ (b, anti-d).

Reference Link (http://www2.slac.stanford.edu/vvc/theory/hadrons.html#Mesons)

Information which describes a set of data.

In the current release, 7.12.8, the Micro database is intended to be used mainly as a quick way of doing analysis.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/analysis/analysis.html#micro)

The Micro database represents the Analysis level and contains all the information to do physics analyses. See the Workbook.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/nanomicro/nanomicro.html)

A measure of a computer's processor speed. Also the name of a computer processor architecture (Microprocessor without Interlocked Pipeline Stages).

Reference Link (http://en.wikipedia.org/wiki/Million_instructions_per_second)

A BaBar Event data format that stores reconstructed detector objects (hits, tracks, clusters, ...) in a compact form. The mini is described in BAD 487.

A particle, typically a muon, producing a small, nearly constant ionization along its flight path. MIPs are often used in calibration because their energy deposition in a detector is easily calculated.

The rate at which a meson (usually a B-meson) is identified with the wrong flavor (i.e. an anti-B meson is identified as a B-meson). It is important to measure this fraction for any algorithm which uses information to tag the meson flavor, since that kno wledge can then be accounted for in the final flavor measurement.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Computing/Offline/Simulation/web/mdc1.html)

In the Offline world, BaBar code is built from well defined objects called modules. Any analysis code written to interface to the BaBar Framework must be written as such a module. A module is written as a C++ class.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/framework1/framework1.html#modules)

The module talk command allows interactive changing of certain module parameters. This is the main feature that allows a user to alter analysis parameters without needing to re-compile the code.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/framework1/framework1.html#modtalk)

Moose is a BaBar executable used for Monte Carlo production. It takes the place of three earlier executables, BgsApp, SimApp, and Bear, and combines all three steps (event generation, detector simulation, and reconstruction) into one package.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/sim/sim.html)

a computing method in which random numbers are generated and used to simulate physics events and detector responses.

For measurement data obtained from a computer simulation of an experiment, the Monte Carlo truth represents the actual conditions and/or parameters used in the simulation. In BaBar, the quantities represented by Monte Carlo truth include information abou t the actual particles generated by the simulation of the beam collision and the detector. Such information includes the particle types, their four-momenta and point of origin, and their decay products (if any).

Known generated values of physical parameters, used as input for the detailed simulation of the detector response, and stored as part of the simulated event data

Muon is the second flavor of charged leptons (in order of increasing mass). It has an electric charge of -1 and a mass of around 106 MeV.

The "nano database" is the most compact form of the "event store" for BABAR data in Objectivity or Kanga format. The nano database is also called the tag database. It contains tag bits (and bytes) as well as information that characterizes the entire ev ent. It does not include information about individual tracks and clusters, which is contained in the "micro database". The contents of the tag and micro databases are documented at on a page linked to the Physics web page under "Information about BABA

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/nanomicro/newest/)

1 Nano Barn (nb) = 10^{-9} barns

A unit of cross section, 1 nb is one billionth of a barn, where 1 barn = 10**-24 cm**2.

Unit of cross section. 1 barn = 10^-28 m^2

Unit of interaction cross section. 1 barn = 1.0e-28 m^2. 1 nb = 1 nano barn = 1.0e-9 barn

number of degrees of freedom

Neural network, (NN), is a tagging method. It is denoted by the string NN in the code.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/analysis/analysis.html#tagging)

This is a BaBar computing environment defined command. It is used to create a new release of the BaBar Software in the current working directory.

Reference Link (http://www.slac.stanford.edu/cgi-wrap/bfman/page?newrel)

Nuclear Instruments and Methods in Physics Research

Reference Link (http://www.elsevier.com/gej-ng/29/35/25/show/Products/NPE/toc.htt)

Non Optimal Tagging, (NOT), is a cut based tagging method.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/analysis/analysis.html#tagging)

A non-resonant decay is one in which a particle decays to a set of stable particles without any intermediate resonant particles in the decay chain.

Novosibirsk is the capital of Siberia. The Budker Institute of Nuclear Physics is based at Novosibirsk. See also: Novosibirsk function

Reference Link (http://www.inp.nsk.su/index.en.shtml)

The Novosibirsk function is usually defined by: f(m_{ES}) = A_S \exp ( -0.5 { \ln^2 [1 + \Lambda \tau \cdot (m_{ES} - m_0) ] / \tau^2 + \tau^2 } ), where \Lambda = \sinh ( \tau \sqrt{\ln 4} ) / ( \sigma \tau \sqrt{\ln 4} ), the peak position is m_0, the width is \sigma, and \tau is the tail parameter.

A tag value giving the total number of charged tracks in an event.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/nanomicro/v8.8/Nano/Event_Params.html)

An Ntuple is a set of events, where for each event the value of a number of variables is recorded. An Ntuple can be viewed as a table with each row corresponding to one event and each column corresponding to given variable. The Ntuple concept is defined and used in the PAW (Physics Analysis Workstation) analysis software package. Web pages: http://wwwinfo.cern.ch/asd/paw/index.html http://wwwinfo.cern.ch/asd/paw/reference_manual/NTUPLE.html

Reference Link (http://wwwinfo.cern.ch/asd/paw/reference_manual/NTUPLE.html)

Object Orientation, (OO), is a programming methodology that transcends an individual language. C++ and Java are two languages that have been designed to support the Object-Oriented paradigm. A well designed object oriented application consists of discti nct objects that interact with each other bysending and receiving messages.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/oo/oo.html)

The OdcNtupleMaker retrieves data from the ambient database and writes them to an ntuple file.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Computing/Online/Databases/OdcNtupleMaker.html)

Data recorded by the Babar data acquisition system

Software that receives the data from the event level of the DataFlow and performs various processing. It is started when you type runOep. One of the most important functions of the OEP is to write the data into XTC files.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Computing/Online/PromptReco/index.html)

Software that controls the BaBar online system. It is started when you type runOrc. The X11 GUI is often called (loosely) the Orc window.

Analysis applications use the OO_FD_BOOTenvironment variable to locate the Federated Database Boot File. Thus it must be set to the location of the Boot File corresponding to the desired database.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/objectivity1/objectivity1.html#terms)

The angle between flight directions of the charged particles produced in a two body decay.

When BaBar users refer to "the database," they usually mean theObjectivity Object Database which contains the detector's constants and event data. There is also an Oracle Relational Database. This database contains administrative data, list of pub lications and drawings, and so forth.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/info_resources/info_resources.html#database)

Orange Room is a conference room, Central Lab (Bld 40), Rm R140/R150 for 80 people. Contact: Public Affairs, x2204

Reference Link (http://www.slac.stanford.edu/gen/pubinfo/slaconly.contact.html)

This type of module acts as the sink of data. There will be modules to direct output to one of several files or to make events available to the online system.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/framework1/framework1.html)

The shift which takes place from 00am until 08am.

usually means track momentum measured in the center-of-mass system.

BaBar (reconstruction and simulation) software is organised in terms of packages. A package is a self contained piece of software intended to perform a well defined task, e.g. find calorimeter clusters, simulate thedrift chamber response.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/srt1/srt1.html)

A package coordinator is a person who maintains a BaBar package. These are components of the software used in BaBar. There are currently more than 1200 packages, of which over 700 have been released.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Computing/Offline/SoftwareAdmin/pkgCoordDuties.txt)

The PAFD is accessable via x.9911 and also has a station on site at SLAC.

Within a user's test release, this is a link to the production directory under BFDIST that corresponds to the base release with which the test release was created. Any code used by the test release, that is not found locally in th test release, will be l ooked for in theparent directory. In this way, a user's local test release, need only include a small number of the total packages used in creating an executable.

Reconstruction of a candidate when not all its daughters are found. A common application is reconstruction of B->D*+ X decays by finding only the X and the soft pion from the D*+ decay. The efficiency increases by a factor of ~10 relative to full reconstruction of the D0.

Reference Link (http://BFROOT/www/Physics/Analysis/AWG/IHBDecays/IHBDecays.html)

Software package that handles particle properties like mass, charge, width.

Subset of the BaBar detector (usually one or more systems) that runs together to take data. A partition is identified by a crate mask, a 32-bit word in which each bit represents a DAQ crate that are participating in the partition. A partition is formed b y the Run Control on INITIALIZE, and dissolved on CLOSE PARTITION.

Sequences and individual modules can be organized into paths. A path is a complete execution sequence, commencing at the input module and terminating at the output module.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/framework1/framework1.html#paths)

A unique identifying number associated with each and every particle used in Monte Carlo simulations of physics processes. The scheme facilitates the connection between event generation and physics analysis. The number encodes information about a particle 's spin, flavor content, and internal quantum numbers.

Reference Link (http://www-pat.fnal.gov/stdhep.html)

One-loop Feynman diagram. Named "penguin" by John Ellis in 1977.

Reference Link (http://xxx.lanl.gov/abs/hep-ex/9804015)

A class that provides access within the BaBar code to PEP-II parameters stored in the conditions database.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Physics/Tools/PepBeams/)

Practical Report and Extraction Language: a powerful scripting language commonly used in tasks ranging from system administration to CGI scripting.

Reference Link (http://www.perl.com)

Perl Universal Daemon (pud) is a stand-alone daemon developed at SLAC. It allows you to perform file system related operations on a remote host.

To be compatible with the Objectivity based database, the objects at each stage of processing must comply with some data structure conventions. Classes that meet these restrictions are said to be persistent or persistent-capable.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/objectivity1/objectivity1.html#terms)

In track helix parameterization, the angle the track momentum makes with the x axis in the x-y plane.

A light detection device. The BaBar DIRC is using 10752 photomultiplier tubes to detect the Cerenkov light.

A light detection device, also called photomultiplier tube. The BaBar DIRC is using 10752 phototubes to detect the Cerenkov light.

pico is a basic text editor that comes with the pine email client.

Reference Link (http://www.washington.edu/pine/)

Unit of cross-section (1 barn = 10^-28 m^2).

To apply measured particle id efficiencies to Monte-Carlo.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Physics/Tools/Pid/PidKilling/PidKilling.html)

The group responsible for the design and maintenance of major infrastructure at SLAC.

The complete set of dataflow hardware which is available to be included in a partition in a given environment.

Point on the track closest to another point (usually the interaction point or the origin of coordinates).

Pom and Flora conference rooms are P&E Bldg (Bld 280), Room 114 (Pom, 10 poeple) and Room 112 (Flora, 20 people). Contact: Kazuko Onaga x4625. Video conference contact for Pom/SLAC 2: Art Bray, x8500.

Reference Link (http://www.slac.stanford.edu/gen/pubinfo/slaconly.contact.html)

Trigger rate reduction method by selecting every Nth event.

prod is a symbolic link to the release currently being used for large scale production. This link is controlled by the production coordinator.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/srt1/srt1.html)

The preliminary version of the BaBar offline analysis production database is called PRV0, short for Production Run Version 0.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/objectivity1/objectivity1.html#prodDb)

Prompt Reconstruction is responsible for running the reconstruction and first pass analysis on the data shortly after it is taken by BaBar. It is also used to reprocess old data when new algorithms and calibration (or other types of) constants have im proved enough to warrent it.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Computing/Online/PromptReco/Operations/OprOp.html)

Synonymous with charged track, normally used to describe the topology of a particle decay as seen in a detector (i.e.: three-prong decay).

A proton is a particle which, along with neutrons, makes up the nuclei of atoms.
Protons are positively charged.
A proton is composed of two up quarks and one down quark.

Reference Link (http://www2.slac.stanford.edu/vvc/theory/hadrons.html)

At SLAC and some other sites the prv0bootcommand has been created to facilitate setting the OO_FD_BOOT variable to the public production database. This command must be issued from your release directory.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/objectivity1/objectivity1.html#prodDb)

A component of the Level-1 Drift Chamber Trigger for selecting high p_T tracks using fine resolution data from DCH axial layers processed by the Track Segment Finders.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Detector/Trigger/trigger_whatsit.html)

Pud ("Perl Universal Daemon") is a stand-alone daemon, which allows you to perform file system related operations on a remote host.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Public/Computing/Databases/experts/administering.shtml)

In data analysis, the "pull" is usually defined as the difference between the measured value of a quantity and its true value, divided by the calculated error on the quantity. It is useful to calculate the pull for a set of measurements and calculate th e mean and RMS of the distribution of pulls. If the error is correctly estimated, then the mean and RMS of the pull distribution should be 0 and 1, respectively.

A fundamental fermion that interacts via the electromagnetic, weak and strong force. There are six types (flavors) of quarks that are known as up, down, charm, strange, top and bottom. Quarks have electric charge of either +2/3 (up, charm, top) or -1/3 ( down, strange, bottom) in units of electron charge. Quarks only exist inside hadrons because they are confined by the strong force field.

The ratio of the second and zeroth Fox-Wolfram moments. Its value ranges from (0,1). This quantity is indicative of the collimation ("jettiness") of an event topology (closer to 1); values of R2 closer to 0 indicate a more spherical event.

r2all is normalized 2nd order Fox-Wolfram moment = FWM(2)/FWM(0) calculated over all final state particles (charged + neutrals).

The radiation length is the scale for describing high energy electromagnetic showers. It is the mean distance over which a high energy electron loses all but 1/e of its energy by bremstrahlung, and is 7/9 of the mean free path for pair production by a high-energy photon. See section 26.4.1 of the particle physics booklet or the reference (link).

Reference Link (http://pdg.lbl.gov/2002/passagerpp.pdf)

The Raw database contains the Raw digis out of the detector. See the Workbook.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/nanomicro/nanomicro.html)

This term refers to the unprocessed (ie not cooked) data as it comes out the detector. There are two forms currently in BaBar. The first and most RAW is the XTC format written by the online event processing system. The second is written into the objectiv ity database by the prompt reconstruction system (this can include monte-carlo truth information but otherwise should be identical in content to the XTC format).

The VME crate's read out controller.

BaBar standard DAQ module that connects to the front-end electronics via optical links and reads out event data.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Detector/DAQ/ReadoutModule/rom.html)

An older version of the VME DAQ Readout Module.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Computing/Online/Concepts/Concepts.htm)

Device for measuring the refractive index

Regional Centers have been established to provide more localized access to BaBar services for collaborators distant from SLAC. A regional center is a BaBar institution that has a local copy of a significant amount of BaBar data.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/unix/unix.html#centers)

A software release consists of a consistent set of packages together with the libraries and binaries created for various machine architectures. Within the $BFROOT/dist/releases subtree there is a subdirectory for each existing release.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/srt1/srt1.html)

The term used to describe a non-initial reconstruction of the data, usually undertaken due to improved calibrations or algorithms.

Detector built with two planes of bakelite coated with graphite assembled to form a 2mm gas gap operated in streamer mode at high voltage (7000-8000V). RPCs are used in the IFR system.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Detector/IFR/plots/ifr_schema.jpg)

the precision of a signal or the capability of a detector to separate two adjacent signals

Reference Link (http://rkb.home.cern.ch/rkb/PH14pp/node176.html#175)

A resonance is a name often given to a particle which has a lifetime so short that it travels no measurable distance within a detector before decaying.
Such particles are detected via the presence of a resonance peak in the invariant mass spectrum of daughter particles.
An event which contains a resonance particle in its decay chain is described as resonant.

Rogue Wave is a software company. BaBar uses it's Tools.h++ product. This class library provides a number of fundamental C++ building blocks such as string, collection, date and time, internationalization, and streaming classes, plus an easier-to-use i nterface to the Standard C++ Library.

Reference Link (http://www.roguewave.com)

Rolling calibration refers to the procedure of determing constants while processing run N and applying these constants when processing run N+1.

".rdl" is the filename extension used for C++ header files to indicate to SRT that these files should be parsed by the ROOT CINT processor to build its runtime dictionary. These files are valid C++ header files but with additional restrictions that al low CINT to parse them. Only classes defined in .rdl files will be visible in an interactive ROOT session. There is no actual RDL "language"; the term "RDL" is modeled upon "DDL", the Data Definition Language used by Objectivity.

Reference Link (http://babar-hn.slac.stanford.edu:5090/HyperNews/get/roothelp/292/2/1.html)

This is a variable used to control the compiler settings during a build. You can set it to include -[no]Optimize or -[no]Debug to turn [off] on optimisation or debugging information.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Computing/Environment/Tools/SRT/index.html)

A run is one batch of analysis within a Framework job.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/framework1/framework1.html#run)

Run coordination and subsystem contacts

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Detector/Operations/runcoor.html http://www.slac.stanford.edu/BFROOT/www/Detector/Operations/Contacts.html)

An individual who coordinates the day-to-day operations and running of the Babar experiment. Ultimately responsible for ensuring high quality and high efficiency data collection.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Detector/Operations/runcoor.html)

A scanner is a machine used to make a representation of a physical object in the digital world. Generally this is to scan paper (with pictures or text). In earlier days, scanner was the job title of a person who counted and measured particle tracks on photographic images of particle interactions (from bubble chambers, cloud chambers, spark chambers, etc.).

The description of the persistent class types that create the BaBar database data model is called the schema.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/objectivity1/objectivity1.html#terms)

Material (usually plastic) that has the property of emitting light when a particle passes through it.

Secure Shell (ssh) is a secure replacement for telnet, rlogin, rsh, and rcp. It uses encryption to keep information that you send over the network from being seen by others. It also uses public and private keys to valida te that the host and client machi nes are who they say they are. Since SCS will disable RSH access soon, BaBar users should start switching to SSH for accessing SLAC machines.

Reference Link (http://www.slac.stanford.edu/comp/unix/ssh.html)

A term for those Monte Carlo signal events not truth-matched

Positive voltage (2 kV) wire in Drift Chamber to which electrons are attracted. Sense wires are 20 um tungsten-rhenium alloy, plated with gold. They are capacitively coupled to the DCH front-end electronics.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Detector/CentralTracker/mechanical/drift_system/index.html)

A Framework sequence is a list of related modules that must be placed together and executed in sequence to provide a defined service to the Framework.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/framework1/framework1.html#sequences)

setboot is a command which should be used by the developers to setup access to their private test federation. For this command to run successfully, test release directory should have file named '.bbobjy' containing a line 'FD_NUMBER := NUM', where NUM is the

A sixth portion of a whole part. In case of the IFR, is the sixth portion in which the barrel is divided in Phi

The silicon vertex detector/tracker, (SVT), is the only tracking device inside the 20cm radius of the BaBar support tube. It is used to measure precisely both impact parameters for charged tracks (z and r - phi).

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/detector/detector.html#systems)

Silo is the name given to a large structure containing thousands of tapes, several tape drives and a robot to allow automatic staging of tapes.

a simulation module which produces the detector response (digitization or digi) given the simple particle position and momentum variables (GHits) generated in a tracking and physics simulation module such as BgsApp.

The system set up to produce Monte Carlo events in BaBar. Production is done at SLAC and in a number (currently 25) remote sites. A number is attached to the acronym to indicate the version

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Computing/Offline/Production)

Magnitude of CP asymmetry due to interference between mixing and decay of certain B decays, such as the gold-plated mode B0 -> J/psi K_S. Beta is one of the angles of the CKM triangle.

Sub-set of events selected with a specific physics signature or decay topology for use in BaBar analyses.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Computing/Operation/SKP.htm)

"Skim" is part of a "stream", that is a collection of events selected on the basis of "tagbits", defined by analysis groups as a pre-selection for sets of physics channels.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Physics/skims/skimsRelease10.html)

BAD 116 Particle ID selector based on SVT, DCH dEdX and DIRC information; mainly used for likelihood-based kaon identification

SLUO was formerly called the Slac-Lbl Users Organization.

Collaboration which measured the left-right asymmetry at the Z resonance. The SLD detector is located in the CEH (Collider Experimental Hall) at the SLC (SLAC Linear Collider) at SLAC.

Reference Link (http://www-sld.slac.stanford.edu/sldwww/sld-working.html)

This set of tools (in the BaBar packages SoftRelTools, SiteConfig, SrtAdmin and PackageList) support the development, building and distribution of BaBar releases.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Computing/Environment/Tools/SRT/)

The complete set of Software Release Tools, (SRT), refers to SoftRelTools. SoftRelTools is itself a package, and is used to install and maintain releases. The BaBar Software Release Tools are based on the Concurrent Versions System, (CVS).

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/srt1/srt1.html)

To achieve good momentum resolution without increasing the tracking volume the BaBar solenoid magnet, (MAG), provides a field of 1.5T. The magnet coil is therefore of superconducting design.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/detector/detector.html#systems)

A regularly-performed calibration of the ElectroMagnetic Calorimeter (EMC). A liquid (Fluorinert) is activated via a neutron generator and pumped past the front of the crystals. The 6.1 MeV decay photons are then detected by the crystals for an ab solu t e calibration at this low energy.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Detector/Calorimeter/RadSource/index.html)

SP2 analysis federation. Used to run analysis based on the Simulation Production Version 2 Monte Carlo.

SP2 production boot file, should not be used by users.

Monte Carlo Simulation produced for run 1 data using Geant 3 and release 8

SP3 analysis federation. Used to run analysis based on the Simulation Production Version 3 Monte Carlo.

SP3 production boot file, should not be used by users.

Monte Carlo simulation production for run 1 and 2 data using Geant 4 and release 10 during 2001-2002

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Computing/Offline/Production/)

SP4 analysis federation. Used to run analysis based on the Simulation Production Version 4 Monte Carlo.

SP4 production boot file, should not be used by users.

This is the database used by the OPR multi-node calibration. Every OPR node writes all calibrations in the separate container.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Computing/Online/PromptReco/OprDatabases.html)

This is a database used in Prompt Calibration to collect information from all the nodes participating. Each node writes to the database and the finalise nodes reads back all the contributions.

srtpath is a BaBar UNIX command that sets up the PATH variable for BaBar's Software Release environment.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/srt1/srt1.html#setup)

Staging is the loading of information from (usually) tape to (usually) disk. This implies that the data will not remain on disk forever and may need to be restaged in the future.

A component of the BaBar DIRC Cerenkov counter which contains very pure water.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Detector/DIRC/dirc_whatsit.html)

STK are the current vendor for SLAC tapes and drives (which are the Eagle technology currently).

Reference Link (http://www.stortek.com/)

This is the BaBar computing environment's version of the glimpse command. Use this command to search the sources of a release for a given pattern.

Reference Link (http://www.slac.stanford.edu/cgi-wrap/bfman/page?srtglimpse)

The super Fox-Wolfram moments are a means of continuum suppression. The underlying idea of continuum suppression techniques is the difference in the event shapes of continuum and BBbar events. Since BBbar events are resonant only little energy is released and these events tend to be spherical. In contrast continuum events exhibit a large energy release and the q and qbar jets tend to emerge collimated back to back. A number of variables have been developed to quantify these differences, one of them are the Fox-Wolfram moments which are already defined elsewhere in this glossary. The l-th Fox-Wolfram moment is defined as H_l=sum_{ij} { |p_i||p_j| P_l(cos(p_i,p_j)) } where p_i is the i-th particle's momentum, and p_l is the l-th Legendre polynomial. The argument of P_l is the cosine of the angle theta_ij between particle i and particle j. The super Fox-Wolfram moments are extensions of the Fox-Wolfram moments, the terms in the summation of H_l are separated into 3 groups: (1) terms involving particles in the B candidate, (2) terms with some particles in the B candidate and others from the rest of the event, (3) terms involving only particles from the rest of the event. A Fisher discriminant (this is already defined elsewhere in this glossary) is then constructed from these terms. This Fisher discriminant is the so-called super Fox-Wolfram moment.

The shift which starts at 4pm and ends at midnight.

A tag is used by BaBar to identify a version of BaBar package. For example, tag V01-02-03 for SoftRelTools signifies major version 01, medium version 02, and minor version 03 of package SoftRelTools.

This refers to contributions by collaborators to keep the BABAR detector running effectively. As defined in the BABAR Collaboration Services Policy: "It is expected that all institutions in the collaboration contribute to the ongoing operation of the experiment. These contributions include detector systems and core software operations and maintenance; coordination and management tasks; physics tools development and infrastructure support; Monte Carlo production; and a host of other jobs both in the operation of the detector and computing

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Organization/Administration/CommonTasks17.pdf)

Tcl scripts are used extensively to set up sequences, paths, and to perform general framework setup such as input files. Many types of sequences are worthless if the order of the modules is wrong or if some modules of the sequence are not enabled. Tcl sc ripts maintain this coherence. There is often a script file for each sequence.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/framework1/framework1.html#tcl)

Technical Design Report: Final document describing the detector design at start of construction.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/TDR/)

Document describing the design of the BaBar Detector at the time of construction.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/TDR/)

The process by which the design of the experiment is review both internally (by those participating in the experiment) and externally (by funding agencies). Critical items include feasibility, performance and budget issues. The Technical Design Report provides a starting point for many of the issues covered.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/TDR/)

test is a symbolic link to the most recent release which has passed basic tests, such as running the full reconstruction on a small number of events. The reconstruction coordinator determines which release this should point to. Not all latest releases will become test releases.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/srt1/srt1.html)

Test beams are used to test detector components before building them. This aids in making sure that it behaves as expected. They are also used in testing new technology to see if it bahaves as hoped.

The basic principle behind SRT, from a user's point of view, is that users create their own, private, releases. In the users case, a test release is typically a very lightweight collection of directories that is tied to a full BaBar release.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/srt1/srt1.html#using_srt)

This is a multi-level acronym. ACE stands for the Adaptive Communications Environment, a set of object-oriented wrappers around a set of operating system calls, e.g., network socket manipulation, timers, etc. ORB stands for Object Request Broker, an ob ject-oriented interprocess(or) communication scheme, in this case adhering to the CORBA (Common Object Request Broker Architecture) standard. CORBA is generally available on all modern computer and OS platforms and for various object-oriented languages

Reference Link (http://www.cs.wustl.edu/~schmidt/TAO.html)

The title of the BaBar operations manual. Short form: The Care Manual.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Detector/Operations/CareAndFeeding/care/care.html)

The name of a detector and an experiment located at the Fermilab colliding ring.

Reference Link (http://www-cdf.fnal.gov/)

This is a collaboration of about 450 physicists who are running a large particle detector at the electron-proton collider HERA at the DESY laboratory in Hamburg. The ZEUS detector is a sophisticated tool for studying the particle reactions provided by the high-energetic beams of the HERA accelerator.

Reference Link (http://www-zeus.desy.de/)

The thrust axis is the direction which maximizes the sum of the longitudinal momenta of the particles. In the case of a background event, the thrust axis corresponds to the axis along the primary quark-antiquark pair produced from e+e- annihilation. For a true B event, the quark-antiquark pair is typically at rest in the C of M frame so the thrust axis tends to be distributed isotropically.

Reference Link (http://www.slac.stanford.edu/BFROOT/dist/releases/newest/BetaCoreTools/BtaThrust.hh)

Large computing centres made available for BaBar needs.

Electronic device for converting a time interval into number.

Time of Flight

Whenever you log in to UNIX via an AFS account, AFS checks the password you supply to make sure that you are who you claim. If you are, AFS grants you a token and thereby authenticates you as a valid AFS user.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/unix/unix.html#afs_and_nfs)

The user interface to the framework is based on Tcl, (Tool Command Language). Tcl, often pronounced "tickle", provides both a scripting language and a command line interpreter. BaBar uses the standard Tcl with some added BaBar specific commands.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/framework1/framework1.html#tcl)

Tool Kit, (Tk), is a graphical interface layed over Tcl.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/framework1/framework1.html#tcl)

Injecting more electrons (or positrons) in the bunches circulating in the PEP rings, to compensate for the beam losses due to finite beam lifetime.

In the EMC world, it indicates a group of crystals of the electro-magnetic calorimeter. For trigger purposes, the crystals are grouped into 280 towers of 24 (for the barrel) or 20/21 (for the endcap) crystals each. In the barrel, the towers all corresp ond to an 8x3 (theta x phi) crystal array. The endcap has not the same 40-fold phi simmetry as the barrel, so the arrangement of crystal in towers is more complex. More documentation including numbering scheme can be found in Babar note #519 (pp.13-1

A collection of hits in the SVT and drift chamber which are fit to an hypothesis trajectory through space. In BaBar, tracks are fit using a "Kalman filter" algorithm which assumes a piecewise helix trajectory hypothesis.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Computing/Offline/Reconstruction/Tracking/trackDocu.html)

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Detector/Trigger/98/tsf_fdr/tsf_fdr.html)

Process of finding charged track signatures in the detector and fitting them to a specific parameterization.

Reconstructed trajectories of charged particles.

In the EMC DAQ system, the transition board is the interface between the fiber-optics and the electrical interface of the IOB.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Detector/DAQ/Calorimeter/WriteUps/EMCDAQDoc.html)

TCP is responsible for verifying the correct delivery of data from client to server on a TCP/IP network. Data can be lost in the intermediate network. TCP adds support to detect errors or lost data and to trigger retransmission until the data is correctl y and completely received.

Reference Link (http://www.stortek.com/)

The trigger system.

Detector system responsible for selecting events for logging. BaBar trigger is multilayered consisting of hardware level 1 (L1) trigger and software level 3 (L3) trigger.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Detector/Trigger/index.html)

In high energy physics, a trigger is a combination of hardware and software components providing a signal whenever an interesting event occurs.

Reference Link (http://rkb.home.cern.ch/rkb/PH14pp/node195.html#SECTION0001950000000000000000)

To unveil the exact numerical result of a measurement that has been hidden (blinded). A blind analysis is designed to avoid experimenter's bias in a measurement.

Reference Link (http://www.slac.stanford.edu/babar-internal/BAD/doc/download?file=00091.002.ps)

A meson containing a b-bbar quark pair, decaying dominantly to either B+B- or B0B0bar. PEP-II typically operates at the Upsilon(4s) resonance energy.

Reference Link (http://pdg.lbl.gov/2004/tables/mxxxbb.ps)

A vertexer is a Beta operator. Given a list or tree of BtaCandidates it returns the most likely common vertex position, vertex momentum, and their errors.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/analysis/analysis.html#vertexing)

Vertexing/kinematic fitting is a mathematical procedure in which one uses physical constraints governing a particle interaction or decay to improve the measurements describing the process. Explicit formulations of these constraints are based on geometric intersections, mass, energy, momentum, etc.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/analysis/analysis.html#vertexing)

BaBar standard scanning ADC module.

One of the elements of the Cabibbo-Kobayashi-Maskawa quark mixing matrix. Vub carries the CP-violating complex phase gamma. Its absolute value is experimentally constrained within the interval from 0.0029 to 0.0045

Reference Link (http://pdg.lbl.gov/2004/reviews/kmmixrpp.ps)

A realtime operating system developed by WindRiver(reg) that offers fast context switches and low interrupt latency. BaBar uses VxWorks in its VME based single board computers.

The Workbook is a tutorial and documentation project intended to introduce members of the BaBar collaboration to the world of BaBar offline analysis.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/workbook.html)

workdir is a package from which you can run aslund, bbsim, and Beta in a simple way. The workdir package may be used to run other applications as well. Simple scripts with flexible options are used to run the programs; input and output remain local to th e workdir directory.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/workdir/workdir.html)

On Sun Solaris there is a nice GUI debugger called workshop.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/doc/workbook/debug/debug.html#gui)

The Y(4S) is a meson. Its quark wave function is (bbar b), its mass about 10.58 GeV. Just like a hydrogen atom a system like (bbar b) can be radially excited. There is a Y(1S), the Y(4S) is the 4th radially excited state with total angular momentum 0.

The Y(4S) is a meson. Its quark wave function is (bbar b), its mass about 10.58 GeV. Just like a hydrogen atom a system like (bbar b) can be radially excited. There is a Y(1S), the Y(4S) is the 4th radially excited state with total angular momentum 0.

A component of the Level-1 drift chamber trigger (upgrade version of 2002/2003). It selects tracks using transverse momentum p_T and origin along the beam line (z) cuts using DCH axial and stereo information processed by the Trac k Segment Finders. It is an upgrade of the earlier PTD discriminator.

Reference Link (http://www.slac.stanford.edu/BFROOT/www/Detector/Trigger/upgrade/cdr/ZpdOverview.pdf)

Babar's friend.

To add an entry to the Glossary use the BaBar Glossary Submission Form.

All comments, requests, and corrections are welcome. Send them by e-mail.

Last significant update: 10-Sept-2002