2,179 research outputs found
Soft QCD results from ATLAS and CMS
The ATLAS and CMS Collaborations have measured properties of minimum bias
events and have determined characteristics of the underlying event in
proton-proton collisions at three LHC centre-of-mass energies. Comparisons to
common phenomenological models and partially to other experiments have been
made. The production of the strange particles K0s, Lambda and Xi is discussed.
Particle correlation studies, in particular Bose-Einstein as well as long- and
short-range angular correlations in proton-proton and lead ion events are
explained.Comment: 4 pages, 7 figures, presented at Rencontres de Moriond, QCD and High
Energy Interactions, La Thuile, March 201
Status and Commissioning of the CMS Experiment
The construction status of the CMS experiment at the Large Hadron Collider and strategies for commissioning the subdetectors, the magnet, the trigger and the data acquisition are described. The first operations of CMS as a unified system, using either cosmic rays or test data, and the planned activities until the startup of the LHC are presented
Memories from the W Boson Discovery
The fascinating story of a major discovery at CERN is outlined. The bold
decision to convert its most powerful, and only recently inaugurated, proton
accelerator to a proton-antiproton collider led to the discovery of the W and Z
bosons -- mediators of the weak interaction -- in a record time, at the
experiments UA1 and UA2. The decisive roles of Carlo Rubbia and Simon van der
Meer, who received the 1984 Nobel Prize for physics, are underlined.Comment: 4 pages, 4 figures. Proceedings of 57th Rencontres de Moriond, QCD
and High Energy Interactions, La Thuile, Italy, 25 March - 1 April 202
B physics and quarkonia at CMS
Selected recent results on B physics and quarkonia are presented. These include a determination of the CP-violating phase Ïs and the decay width difference ÎÎs of the light and heavy Bs states with Bs â J/Ï ÎŠ(1020), prompt double-differential production cross sections of J/Ï and Ï(2S), and polarization measurements for J/Ï, Ï(2S), Ï(1S), Ï(2S), and Ï(3S). Results are based on proton-proton data recorded at the LHC at centre-of-mass energies of 7 or 8 TeV
The CMS Drift Tube Trigger Track Finder
Muons are among the decay products of many new particles that may be discovered at the CERN Large Hadron Collider. At the first trigger level the identification of muons and the determination of their transverse momenta and location is performed by the Drift Tube Trigger Track Finder in the central region of the Compact Muon Solenoid experiment, using track segments detected in the Drift Tube muon chambers. Track finding is performed both in pseudorapidity and azimuth. Track candidates are ranked and sorted, and the best four are delivered to the subsequent high level trigger stage. The concept, design, control and simulation software as well as the expected performance of the system are described. Prototyping, production and tests are also summarized
Pattern Comparator Trigger (PACT) for the muon system of the CMS experiment
The general scheme for the fast, pipelined first level trigger on high pt muons in the CMS detector at LHC is presented. The prototype PACT system was tested in the high momentum muon beams in the RD5 experiment during 1993/94 runs. The obtained efficiency curves are shown
Measurement of hadronic shower punchthrough in magnetic field
The total punchthrough probability of showers produced by negative pions, positive pions, positive kaons and protons, has been measured as a function of depth in an absorber in a magnetic field ranging from 0 to 3 Tesla. The incident particle momentum varied from 10 to 300 GeV/c. The lateral shower development and particle multiplicity at several absorber depths have been determined. The measurements are compared with the predictions of Monte Carlo simulation programs
- âŠ