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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)
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
