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BaBar Glossary Search Tool

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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.

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