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Title: Analysis of Luminosity Data in BaBar

Abstract

Luminosity is a value describing the number of interactions between particles when their respective beams collide. The BaBar (B and B-bar) ambient database and the Oracle server contain archived measurements of instantaneous luminosity from two separate detectors. It is important to understand these data to describe the performance of the B-Factory. Extracting these data, the more reliable PEP-II (Positron Electron Two) luminosity detector can be calibrated to the data collected by the more accurate BaBar L3 (Level 3) detector. Using the ROOT programming language and standard BaBar tools for data extraction, graphs and statistics are generated. Some logistical errors contained in the logbook are also corrected. These programs help aid in understanding both what is happening within the B-Factory, as well as the correlations between the interrelationship of detector data and the information recorded in the logbook.

Authors:
Publication Date:
Research Org.:
Stanford Linear Accelerator Center, Menlo Park, CA (US)
Sponsoring Org.:
USDOE Office of Science (US)
OSTI Identifier:
833111
Report Number(s):
SLAC-TN-04-057
TRN: US0406475
DOE Contract Number:
AC03-76SF00515
Resource Type:
Technical Report
Resource Relation:
Other Information: PBD: 3 Sep 2004
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; 99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE; ELECTRON BEAMS; BEAM LUMINOSITY; PERFORMANCE; COLLIDING BEAMS; PEP STORAGE RINGS; RADIATION DETECTORS; DATA ANALYSIS; COMPUTER CALCULATIONS

Citation Formats

Schiller, R. Analysis of Luminosity Data in BaBar. United States: N. p., 2004. Web. doi:10.2172/833111.
Schiller, R. Analysis of Luminosity Data in BaBar. United States. doi:10.2172/833111.
Schiller, R. Fri . "Analysis of Luminosity Data in BaBar". United States. doi:10.2172/833111. https://www.osti.gov/servlets/purl/833111.
@article{osti_833111,
title = {Analysis of Luminosity Data in BaBar},
author = {Schiller, R.},
abstractNote = {Luminosity is a value describing the number of interactions between particles when their respective beams collide. The BaBar (B and B-bar) ambient database and the Oracle server contain archived measurements of instantaneous luminosity from two separate detectors. It is important to understand these data to describe the performance of the B-Factory. Extracting these data, the more reliable PEP-II (Positron Electron Two) luminosity detector can be calibrated to the data collected by the more accurate BaBar L3 (Level 3) detector. Using the ROOT programming language and standard BaBar tools for data extraction, graphs and statistics are generated. Some logistical errors contained in the logbook are also corrected. These programs help aid in understanding both what is happening within the B-Factory, as well as the correlations between the interrelationship of detector data and the information recorded in the logbook.},
doi = {10.2172/833111},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Fri Sep 03 00:00:00 EDT 2004},
month = {Fri Sep 03 00:00:00 EDT 2004}
}

Technical Report:

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  • The BaBar experiment has recently revised its Analysis Model. One of the key ingredient of BaBar new Analysis Model is the support of the capability to add to the Event Store user defined data, which can be the output of complex computations performed at an advanced stage of a physics analysis, and are associated to analysis objects. In order to provide flexibility and extensibility with respect to object types, template generic programming has been adopted. In this way the model is non-intrusive with respect to reconstruction and analysis objects it manages, not requiring changes in their interfaces and implementations. Technologicalmore » details are hidden as much as possible to the user, providing a simple interface. In this paper we present some of the limitations of the old model and how they are addressed by the new Analysis Model.« less
  • The DIRC (acronym for Detection of Internally Reflected Cherenkov (light)) is the ring imaging Cherenkov detector of the BaBar detector at the Pep-II ring of SLAC. It provides the identification of pions, kaons and protons for momenta up to 4 GeV/c with high efficiency. This is needed to reconstruct CP-violating B-decay final states and to provide B-meson flavour tagging for time dependent asymmetry measurements. The DIRC radiators consists of long rectangular bars made of synthetic fused silica and the photon detector is a water tank equipped with an array of 10,752 conventional photomultipliers. At the end of the year 2000more » BaBar has recorded about 22 million {bar B}B pairs reaching the design luminosity of L = 3 x 10{sup 33}/cm{sup 2}s. The ability to keep the beam background level low at highest collision rates and the long term reliability of the DIRC components during continuous data taking are requirements of BaBar to accomplish its physics program.« less
  • It has been proposed that Limited Streamer Tubes (LST) be used in the current upgrade of the muon detector in the BaBar detector. An LST consists of a thin silver plated wire centered in a graphite-coated cell. One standard LST tube consists of eight such cells, and two or three such tubes form an LST module. Under operation, the cells are filled with a gas mixture of CO{sub 2}, argon and isobutane. During normal operation of the detector, the gas will be flushed out of the system at a constant low rate of one volume change per day. During timesmore » such as installation, however, it is often desired to flush and change the LST gas volumes very rapidly, leading to higher than normal pressure which may damage the modules. This project studied this pressure as a function of flow rate and the number of modules that are put in series in search of the maximal safe flow rate at which to flush the modules. Measurements of pressure drop versus flow rate were taken using a flow meter and a pressure transducer on configurations of one to five modules put in series. Minimal Poly-Flo tubing was used for all connections between test equipment and modules. They contributed less than 25% to all measurements. A ratio of 0.00022 {+-} 0.00001 mmHg per Standard Cubic Centimeter per Minute (SCCM) per module was found, which was a slight overestimate since it included the contributions from the tubing connections. However, for the purpose of finding a flow rate at which the modules can be safely flushed, this overestimate acts as a safety cushion. For a standard module with a volume of 16 liters and a known safe overpressure of 2 inches of water, the ratio translates into a flow rate of 17000 {+-} 1000SCCM and a time requirement of 56 {+-} 5 seconds to flush an entire module.« less
  • As part of the BaBar project at SLAC to study the properties of B mesons, we have carried out a study of the exclusive charmless semileptonic decay mode B {yields} wlv, which can be used to determine the Cabbibo-Kobayashi-Maskawa matrix element V{sub ub}. Using simulated event samples, this study focuses on determining criteria on variables for selection of B {yields} wlv signal and suppression of background from other types of B{bar B} events and continuum processes. In addition, we determine optimal cuts on variables to ensure a good neutrino reconstruction. With these selection cuts, we were able to achieve amore » signal-to-background ratio of 0.68 and a signal efficiency of the order of 1%. Applying these cuts to a sample of 83 million B{bar B} events recorded by BaBar in e{sup +}e{sup -} collisions at the {Upsilon}(4S) resonance, we obtain a yield of 115 {+-} 19 B {yields} wlv decays.« less