44,517 research outputs found
Measurements of single top quark production processes with the ATLAS and CMS experiments
No full textThis report contains a brief summary of the latest single top quark production cross-section measurements performed by the ATLAS and CMS
collaborations on pp collisions collected during Run 2 of the LHC. Various results for t−channel, s−channel and W associated single top production
are discussed. Particular attention is given to the main techniques used by the analyses and the main systematic uncertainties limiting these precise measurements
A new boson with a mass of 125 GeV observed with the CMS experiment at the Large Hadron Collider
No full textThe Higgs boson was postulated nearly five decades ago within the framework of the standard model of particle physics and has been the subject of numerous searches at accelerators around the world. Its discovery would verify the existence of a complex scalar field thought to give mass to three of the carriers of the electroweak force-the W+, W-, and Z(0) bosons-as well as to the fundamental quarks and leptons. The CMS Collaboration has observed, with a statistical significance of five standard deviations, a new particle produced in proton-proton collisions at the Large Hadron Collider at CERN. The evidence is strongest in the diphoton and four-lepton (electrons and/or muons) final states, which provide the best mass resolution in the CMS detector. The probability of the observed signal being due to a random fluctuation of the background is about 1 in 3 x 10(6). The new particle is a boson with spin not equal to 1 and has a mass of about 1.25 giga-electron volts. Although its measured properties are, within the uncertainties of the present data, consistent with those expected of the Higgs boson, more data are needed to elucidate the precise nature of the new particle
First results and prospects in B physics at CMS
No full textThe first results in b physics obtained by the CMS collaboration from the data collected in pp collisions at 7 TeV at the LHC. In particular, results are reported on heavy quarkoniun production (J/ψ) and Y), and on inclusive b jet production cross section. Progress on exclusive reconstructions is also mentioned
Performance Study of the CMS Barrel Resistive Plate Chambers with Cosmic Rays
No full textIn October and November 2008, the CMS collaboration conducted a programme of cosmic ray data taking, which has recorded about 270 million events. The Resistive Plate Chamber system, which is part of the CMS muon detection system, was successfully operated in the full barrel. More than 98% of the channels were operational during the exercise with typical detection efficiency of 90%. In this paper, the performance of the detector during these dedicated runs is reported
CMS collaboration Summer 2012
No full textThe CMS collaboration in front of the real size CMS poster at CERN P
Luminosity determination using Z boson production at the CMS experiment
No full textData 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
Data Quality Monitoring and Performance Studies of the Resistive Plate Chamber Detector at the CMS Experiment at LHC.
No full textThe CMS detector is a sophisticated and massive system: 7 different detector technologies, a high number of front-end electronic channels (10^7) , an input rate of 10^9 interactions per second, a trigger able to reduce the frequency by a factor 10^5, and online computer farms with a storage capability rates of about 10^2 MB/s. CMS is foreseen to take data, with high efficiency, for
over 15 years. Clearly, assuring pristine and stable behavior of each of its components is critical and delicate task.
The CMS collaboration designed and built, in tandem with detector commissioning, a high-level Data Quality Monitoring (DQM) system for the reliable certification of recorded data for physics analyses. DQM debugs hardware, monitors detector and trigger performance behavior, and highlight problems or malfunctioning by processing calibration and physics data.
Definition of the requirements, design, and development of the RPC DQM system, as well as its use to study detector and trigger performance, have been the focus of this doctoral thesis work
Author Correction: A portrait of the Higgs boson by the CMS experiment ten years after the discovery (Nature, (2022), 607, 7917, (60-68), 10.1038/s41586-022-04892-x)
No full textCorrection to: Nature Published online 4 July 2022 In the version of this article initially published, CMS Collaboration author names, affiliations and acknowledgements were omitted and have now been included in the HTML and PDF versions of the article.SCOAP
CMS Computing Software and Analysis Challenge 2006
No full textThe CMS (Compact Muon Solenoid) collaboration is making a big effort to test the workflow and the dataflow associated with the data handling model. With this purpose the computing, software and analysis Challenge 2006, namely CSA06, started the 15th of September. It was a 50 million event exercise that included all the steps of the analysis chain, like the prompt reconstruction, the data streaming, calibration and alignment iterative executions, the data distribution to regional sites, up to the end-user analysis. Grid tools provided by the LCG project are also experimented to gain access to the data and the resources by providing a user friendly interface to the physicists submitting the production and the analysis jobs. An overview of the status and results of the CSA06 is presented in this work
Observation of a new particle in the search for the Standard Model Higgs boson at the CMS detector
No full textThe discovery of the Standard Model (SM) Higgs boson is one of the
primary physics objectives of the Large Hadron Collider at CERN. This
thesis describes a search carried out for the SM Higgs boson on data collected
during the 2011 and 2012 proton-proton (pp) collision runs with
the CMS detector corresponding to integrated luminosities of 5:1fb-1
and 5:3fb-1 respectively. A detailed description of the search for the
SM Higgs boson decaying to two photons from the full dataset collected
at CMS during the 2011 pp collision run is provided. In particular, the
development of signal and background modelling techniques used for
statistical interpretations of the data are highlighted. Results of the
search using these techniques from the 2011 dataset are presented. In
addition, an update to the analysis including data taken during 2012
is described and the results from the combined 2011 and 2012 analyses
given. Results from the combination of several Higgs decay channels at
CMS are reported, including those presented in the International Conference
on High Energy Physics in July 2012 at which the announcement of
discovery was made. Ongoing studies to ascertain the properties of the
new particle are discussed and preliminary results from the combined 7
and 8 TeV datasets (corresponding to 5:1fb-1 and 12:2fb-1 respectively)
are presented.Open Acces
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