1,822,179 research outputs found
Luminosity determination using Z boson production at the CMS experiment
Full text linkData Availability Statement: This manuscript has no associated data or
the data will not be deposited. [Authors’ comment: Release and preser
vation of data used by the CMS Collaboration as the basis for publi
cations is guidedbytheCMSpolicyasstatedinhttps://cms-docdb.cern.
ch/cgibin/PublicDocDB/RetrieveFile?docid=6032&filename=CMSD
ataPolicyV1.2.pdf&version=2. CMS data preservation,re-use and open
access policy.]A preprint version of the article is available at arXiv:2309.01008v2 [hep-ex], https://arxiv.org/abs/2309.01008v2 . Comments: Replaced with the published version. Added the journal reference and the DOI. All the figures and tables can be found at: https://cms-results.web.cern.ch/cms-results/public-results/publications/LUM-21-001 (CMS Public Pages)The measurement of Z boson production is presented as a method to determine the integrated luminosity of CMS data sets. The analysis uses proton–proton collision data, recorded by the CMS experiment at the CERN LHC in 2017 at a center-of-mass energy of 13 TeV . Events with Z bosons decaying into a pair of muons are selected. The total number of Z bosons produced in a fiducial volume is determined, together with the identification efficiencies and correlations from the same data set, in small intervals of 20 pb-1 of integrated luminosity, thus facilitating the efficiency and rate measurement as a function of time and instantaneous luminosity. Using the ratio of the efficiency-corrected numbers of Z bosons, the precisely measured integrated luminosity of one data set is used to determine the luminosity of another. For the first time, a full quantitative uncertainty analysis of the use of Z bosons for the integrated luminosity measurement is performed. The uncertainty in the extrapolation between two data sets, recorded in 2017 at low and high instantaneous luminosity, is less than 0.5%. We show that the Z boson rate measurement constitutes a precise method, complementary to traditional methods, with the potential to improve the measurement of the integrated luminosity.SCOAP
Alignment of the CMS silicon strip tracker during stand-alone commissioning
Full text linkThis is the Pre-print version of the Article. The official published version of the paper can be accessed from the link below - Copyright @ 2009 IOPThe results of the CMS tracker alignment analysis are presented using the data from cosmic tracks, optical survey information, and the laser alignment system at the Tracker Integration Facility at CERN. During several months of operation in the spring and summer of 2007, about five million cosmic track events were collected with a partially active CMS Tracker. This allowed us to perform first alignment of the active silicon modules with the cosmic tracks using three different statistical approaches; validate the survey and laser alignment system performance; and test the stability of Tracker structures under various stresses and temperatures ranging from +15C to -15C. Comparison with simulation shows that the achieved alignment precision in the barrel part of the tracker leads to residual distributions similar to those obtained with a random misalignment of 50 (80) microns in the outer (inner) part of the barrel.This work has been supported by: the Austrian Federal Ministry of Science and Research; the Belgium Fonds de la Recherche Scientifique and Fonds voor Wetenschappelijk Onderzoek; the Academy of Finland and
Helsinki Institute of Physics; the Institut National de Physique Nucléaire et de Physique des Particules / CNRS, France; the Bundesministerium für Bildung und Forschung, Germany; the Istituto Nazionale di Fisica Nucleare, Italy; the Swiss Funding Agencies; the Science and Technology Facilities Council, UK; the US Department of Energy, and National Science Foundation. Individuals
have received support from the Marie-Curie IEF program (European Union) and the A. P. Sloan Foundation
Development of the CMS detector for the CERN LHC Run 3
No full textA preprint version of this article is available at arXiv:2309.05466v1 [physics.ins-det], https://arxiv.org/abs/2309.05466v1 . Comments: Submitted to the Journal of Instrumentation. All figures and tables can be found at https://cms-results.web.cern.ch/cms-results/public-results/publications/PRF-21-001 (CMS Public Pages). Report number: CMS-PRF-21-001, CERN-EP-2023-136.Since the initial data taking of the CERN LHC, the CMS experiment has undergone substantial upgrades and improvements. This paper discusses the CMS detector as it is configured for the third data-taking period of the CERN LHC, Run 3, which started in 2022. The entire silicon pixel tracking detector was replaced. A new powering system for the superconducting solenoid was installed. The electronics of the hadron calorimeter was upgraded. All the muon electronic systems were upgraded, and new muon detector stations were added, including a gas electron multiplier detector. The precision proton spectrometer was upgraded. The dedicated luminosity detectors and the beam loss monitor were refurbished. Substantial improvements to the trigger, data acquisition, software, and computing systems were also implemented, including a new hybrid CPU/GPU farm for the high-level trigger.SCOAP3
Quarks: The Next Generation? - Pictures for a CMS briefing
No full textThese are figures for the CMS briefing "Quarks: The Next Generation?
The CMS Tracker operation and performance at the Magnet Test and Cosmic Challenge
Full text linkDuring summer 2006 a fraction of the CMS silicon strip tracker was operated in a comprehensive slice test called the Magnet Test and Cosmic Challenge (MTCC). At the MTCC, cosmic rays detected in the muon chambers were used to trigger the readout of all CMS sub-detectors in the general data acquisition system and in the presence of the 4 T magnetic field produced by the CMS superconducting solenoid. This document describes the operation of the Tracker hardware and software prior, during and after data taking. The performance of the detector as resulting from the MTCC data analysis is also presented. © 2008 IOP Publishing Ltd and SISSA.0SCOPUS: ar.jinfo:eu-repo/semantics/publishe
Radiation hardness qualification of PbWO4 scintillation crystals for the CMS Electromagnetic Calorimeter
Full text linkThis is the Pre-print version of the Article. The official published version can be accessed from the link below - Copyright @ 2010 IOPEnsuring the radiation hardness of PbWO4 crystals was one of the main priorities during the construction of the electromagnetic calorimeter of the CMS experiment at CERN. The production on an industrial scale of radiation hard crystals and their certification over a period of several years represented a difficult challenge both for CMS and for the crystal suppliers. The present article reviews the related scientific and technological problems encountered
Muon identification using multivariate techniques in the CMS experiment in proton-proton collisions at sqrt(s) = 13 TeV
No full textAn arXiv ePrint: arXiv:2310.03844v2 [hep-ex], is available online at: https://arxiv.org/abs/2310.03844v2 . Comments: Replaced with the published version. Added the journal reference and the DOI. All the figures and tables can be found at https://cms-results.web.cern.ch/cms-results/public-results/publications/MUO-22-001 (CMS Public Pages)The identification of prompt and isolated muons, as well as muons from heavy-flavour hadron decays, is an important task. We developed two multivariate techniques to provide highly efficient identification for muons with transverse momentum greater than 10 GeV. One provides a continuous variable as an alternative to a cut-based identification selection and offers a better discrimination power against misidentified muons. The other one selects prompt and isolated muons by using isolation requirements to reduce the contamination from nonprompt muons arising in heavy-flavour hadron decays. Both algorithms are developed using 59.7 fb-1 of proton-proton collisions data at a centre-of-mass energy of √(s)=13 TeV collected in 2018 with the CMS experiment at the CERN LHC.SCOAP3
CMS tracking performance results from early LHC operation
Full text linkThis is the Pre-print version of the Article. The official published version of the Paper can be accessed from the link below - Copyright @ 2010 Sringer VerlagThe first LHC pp collisions at centre-of-mass energies of 0.9 and 2.36 TeV were recorded by the CMS detector in December 2009. The trajectories of charged particles produced in the collisions were reconstructed using the all-silicon Tracker and their momenta were measured in the 3.8 T axial magnetic field. Results from the Tracker commissioning are presented including studies of timing, efficiency, signal-to-noise, resolution, and ionization energy. Reconstructed tracks are used to benchmark the performance in terms of track and vertex resolutions, reconstruction of decays, estimation of ionization energy loss, as well as identification of photon conversions, nuclear interactions, and heavy-flavour decays
Combination of measurements of the top quark mass from data collected by the ATLAS and CMS experiments at and 8 TeV
No full textA preprint version of the article is available online at: arXiv:2402.08713v1 [hep-ex], https://arxiv.org/abs/2402.08713v1 . Comments: Submitted to Physical Review Letters. All figures and tables can be found at https://cms-results.web.cern.ch/cms-results/public-results/publications/TOP-22-001 (CMS Public Pages). Report number: CMS-TOP-22-001, ATLAS-TOPQ-2019-13, CERN-EP-2024-020.A combination of fifteen top quark mass measurements performed by the ATLAS and CMS experiments at the LHC is presented. The datasets used correspond to an integrated luminosity of up to 5 and 20 fb^−1 of proton-proton collisions at center-of-mass energies of 7 and 8 TeV, respectively. The combination includes measurements in top quark pair events that exploit both the semileptonic and hadronic decays of the top quark, and a measurement using events enriched in single top quark production via the electroweak channel. The combination accounts for the correlations between measurements and achieves an improvement in the total uncertainty of 31% relative to the most precise input measurement. The result is =172.52±0.14(stat)±0.30(syst) GeV, with a total uncertainty of 0.33 GeV.SCOAP3
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