121671301
A large-area modular electromagnetic shower detector for the CERN intersecting storage rings
Abstract We describe the design and performances of a large-area (13 m 2 ) shower detector built for an experiment at the CERN ISR to detect electrons and gamma rays with energies up to 4 GeV. The main characteristics of the detector are: a) linearity of the energy response from 0.5 to 4 GeV; b) good energy, time and space resolutions; c) modularity of the mechanical assembly; d) low cost of construction.
120145616
The inclusive transverse-momentum distribution in hadronic systems produced in proton-proton collisions
Summary. The single.particle inclusive transverse-momentum distribution in the multiparticle systems produced in low-1~T proton-proton interactions at ~- 30 and 62 GoV has been studied. The analysis was performed removing from the final state the leading proton and redefining the effective hadronie energy available for particle production. Excellent agreement for effective hadronic energies up to 13 GoV is found between (pp) and (e+e-). At higher energy the (pp) data show a less pronounced growth than the (e+e -) data.
122652831
Results of a search for free quarks with a large avalanche chamber in high-energy neutrino interactions
SummaryA search for free quarks liberated via neutrino-quark coupling using the highest possible available energy was performed at CERN (WA-44 experiment) in the neutrino wide-band beam. The neutrino interactions take place in a 23 ton lead target. A forward large avalanche chamber is triggered when one or more charged particles from the neutrino (antineutrino) interactions cross two sets of counter hodoscopes. Ionization measurements in the avalanche chamber have been performed using two measuring machines: HPD in Bologna and PERPR in Frascati. The 6% expected statistical fluctuations in the ionization measurements have been obtained on one metre long tracks. This allowed an accurate analysis of the data to search in the 1/3 and even in the 2/3 charge regions. About 3.7·105 tracks were observed in the chamber, from about 105 neutrino (antineutrino) interactions. The analysis of the digitized data has selected 20 candidates for fractional charges. After a detailed analysis of both pictures and measurements, and a complete investigation of all possible instrumental effects, one event remains as a fractional charge (+1/3) candidate. This candidate has a small probability to be an edge effect in the apparatus. However this event is at the expected level of candidate events from the rejection power of our detector. Upper limits (90% c.l.) on the flux of quarks produced in both neutrino and antineutrino interactions are at the level of a few 10−5.
117276470
New ISR physics: Heavy flavors and multihadronic final states
122513738
The ratio of charged-to-total energy in high-energy proton-proton interactions
Abstract The ratio of charged-to-total energy in multiparticle hadronic systems produced in pp interactions has been measured. The analysis has been performed using our technique of subtracting the “leading” baryon effects. The results are compared with e + e − annihilation data.
118133322
A prediction for the total charge multiplicity in hadronic interactions at extreme high energies
2971912
The CMS tracker Data Quality Monitoring expert GUI
Data Quality Monitoring (DQM) is mandatory in a high energy physics experiment like the Compact Muon Solenoid (CMS) at the CERN Large Hadron Collider (LHC). For the CMS Silicon Strip Tracker, the largest detector of this kind ever built, the DQM tasks translate into monitoring of 15148 silicon detector modules for a total of 9.3 million channels. An expert level Graphical User Interface has been developed to manage this highly granular information where the statistical characteristics of more than 350000 histograms are analyzed online during data-taking in order to raise warnings or alarms. In addition, specific quantities can be recalled on demand for problems investigation or online feedback on the data quality.
121781476
First performance studies of a pixel-based trigger in the CMS experiment
An important tool for the discovery of new physics at LHC is the design of a low level trigger with an high power of background rejection. The contribution of pixel detector to the lowest level trigger at CMS is studied focusing on low-energy jet identification, matching the information from calorimeters and pixel detector. In addition, primary vertex algorithms are investigated. The performances are evaluated in terms of, respectively, QCD rejection and multihadronic jets final states efficiency.
123498730
CMS tracker performance
Abstract The Compact Muon Solenoid (CMS) experiment is a multipurpose high energy physics detector operated at the CERN Large Hadron Collider (LHC) near Geneva, Switzerland. The current status and performance of the CMS silicon tracker after 2 years of p–p collisions at s = 7 TeV are reviewed.
119968739
CMS Silicon Strip Tracker Commissioning and Preliminary Performances
The Silicon Strip Tracker (SST) of the Compact Muon Solenoid (CMS) Experiment at the CERN Large Hadron Collider (LHC) is the world's largest silicon microstrip detector. The SST is composed of four subdetectors which were integrated into the Tracker Support Tube (TST) at the CERN Tracker Integration Facility (TIF) in March 2007. After the insertion of the TST into CMS in December 2007, the first data taking of CMS with the SST included took place in July 2008 without magnetic field and one month later with a magnetic field of 3.8 Tesla. The SST was ready for the LHC start-up of September 10, 2008. The main aspects of the SST commissioning and a description of the problems encountered and solved so far are summarized here together with some preliminary performance evaluation.