Search for High-mass Dimuon Resonances and Study of Endcap Muon System Neutron-induced Background Hits with the Compact Muon Solenoid Detector

Search for High-mass Dimuon Resonances and Study of Endcap Muon System Neutron-induced Background Hits with the Compact Muon Solenoid Detector
Title Search for High-mass Dimuon Resonances and Study of Endcap Muon System Neutron-induced Background Hits with the Compact Muon Solenoid Detector PDF eBook
Author Christian Schnaible
Publisher
Pages 219
Release 2019
Genre
ISBN

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This thesis presents a search for narrow resonances in the dimuon invariant mass spectrum using data obtained from proton-proton collisions at $\sqrt{s}=13$ TeV collected by the CMS detector at the CERN LHC. We describe the analysis and results of the data collected in 2018, which corresponds to an integrated luminosity of 63.1 fb$^{-1}$. We also present results of the combination of the 2016, 2017, and 2018 data sets, as well as the results of the combination with the dielectron analysis, which correspond to a total integrated luminosity of up to 140 fb$^{-1}$. The results are interpreted in terms of the upper limit on the ratio of the cross section of a new resonance to that of the $Z$ boson. We also compute the corresponding lower limits on the masses of various benchmark resonances. No evidence for beyond the standard model physics is observed in the 2018 data set, or in any of the combined data sets. Relevant for the high masses where we perform our search, we also discuss the reconstruction and performance of high momentum muons in CMS. In the appendix, we present a study of neutron-induced background hits in CMS endcap muon chambers.

Performance and Calibrations of the Compact Muon Solenoid Muon System and a Search for Sphalerons at the Large Hadron Collider

Performance and Calibrations of the Compact Muon Solenoid Muon System and a Search for Sphalerons at the Large Hadron Collider
Title Performance and Calibrations of the Compact Muon Solenoid Muon System and a Search for Sphalerons at the Large Hadron Collider PDF eBook
Author Cameron Bravo
Publisher
Pages 142
Release 2018
Genre
ISBN

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This thesis first presents a detailed study of the Compact Muon Solenoid (CMS) Cathode Strip Chamber track stubs used to build muon tracks in the first layer of filtering, done in hardware, of the data. We study the spatial and angular resolutions of the track stubs with respect to the reconstructed hits using the full granularity data. We then move to a general description of a new technology, Gas Electron Multipliers (GEM), which is to be used in a near-future upgrade to the system. The characterization and calibration of the front-end electronics of the GEMs is discussed in detail. It is demonstrated that the noise of the electronics is sufficiently low to allow high efficiency operation of the technology with the first prototype GEM detector for the new subsystem. We then discuss the phenomenology of sphaleron-induced transition in proton-proton collisions. A new Monte Carlo generator is built to study this phenomenology in detail. We then perform a search analysis of the $35.9~\text{fb}^{-1}$ of data collected by the CMS detector in 2016. We set the first experimental upper limit on sphaleron production in proton-proton collisions.

Search for New Physics in the Compact Muon Solenoid (CMS) Experiment and the Response of the CMS Calorimeters to Particles and Jets

Search for New Physics in the Compact Muon Solenoid (CMS) Experiment and the Response of the CMS Calorimeters to Particles and Jets
Title Search for New Physics in the Compact Muon Solenoid (CMS) Experiment and the Response of the CMS Calorimeters to Particles and Jets PDF eBook
Author
Publisher
Pages 113
Release 2008
Genre
ISBN

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A Monte Carlo study of a generic search for new resonances beyond the Standard Model (SM) in the CMS experiment is presented. The resonances are axigluon, coloron, E6 diquark, excited quark, W', Z', and the Randall-Sundrum graviton which decay to dijets. The dijet resonance cross section that the CMS can expect to discover at a 5[sigma] significance or to exclude at 95% confidence level for integrated luminosities of 100 pb-1, 1 fb-1, and 10 fb-1 is evaluated. It is shown that a 5[sigma] discovery of a multi-TeV dijet resonance is possible for an axigluon, excited quark, and E6 diquark. However, a 5[sigma] discovery can not be projected with confidence for a W', Z' and the Randall-Sundrum graviton. On the other hand, 95% CL exclusion mass regions can be measured for all resonances at high luminosities. In the second part of this dissertation, the analyses of the 2006 test beam data from the combined electromagnetic and hadronic barrel calorimeters are presented. The CMS barrel calorimeters response to a variety of beam particles in a wide momenta range (1 to 350 GeV/c) is measured. Furthermore, using these beam data, the expected performance of the barrel calorimeters to jets is predicted.

A Search for New Resonances with the Dijet Angular Ratio Using the Compact Muon Solenoid Experiment

A Search for New Resonances with the Dijet Angular Ratio Using the Compact Muon Solenoid Experiment
Title A Search for New Resonances with the Dijet Angular Ratio Using the Compact Muon Solenoid Experiment PDF eBook
Author Jason Michael St. John
Publisher
Pages 280
Release 2012
Genre
ISBN

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Abstract: A search for dijet resonances is performed using 2.2 fb-1 of proton-proton collision data at [Special characters omitted.] = 7 TeV recorded by the CMS detector at CERN. The study is based on the dijet angular ratio, the ratio of the number of events with the two leading jets having pseudorapidity difference |An|

A Search for New Resonances with the Dijet Angular Ratio Using the Compact Muon Solenoid Experiment

A Search for New Resonances with the Dijet Angular Ratio Using the Compact Muon Solenoid Experiment
Title A Search for New Resonances with the Dijet Angular Ratio Using the Compact Muon Solenoid Experiment PDF eBook
Author
Publisher
Pages
Release 2012
Genre
ISBN

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A search for dijet resonances is performed using 2.2 fb$^{-1}$ of proton-proton collision data at $\sqrt{s}$ = 7 TeV recorded by the CMS detector at CERN. The study is based on the dijet angular ratio, the ratio of the number of events with the two leading jets having pseudorapidity difference

Compact Muon Solenoid Experiment Discovery Potential for Supersymmetry in Same-charge Di-lepton Events

Compact Muon Solenoid Experiment Discovery Potential for Supersymmetry in Same-charge Di-lepton Events
Title Compact Muon Solenoid Experiment Discovery Potential for Supersymmetry in Same-charge Di-lepton Events PDF eBook
Author Yuriy Aleksandrovich Pakhotin
Publisher
Pages
Release 2010
Genre
ISBN

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ABSTRACT: Same-charge di-lepton events provide a very clean experimental signature for Supersymmetry (SUSY) search. This work studies the Compact Muon Solenoid (CMS) experiment search potential for new physics with same-charge, isolated di-leptons accompanied by jets and large missing transverse energy. The results show that CMS sensitivity for new physics at 7 TeV with integrated luminosity 100 pb ... 1 will exceed current Tevatron limits. Muon detection for SUSY discovery in the forward direction is accomplished using cathode strip chambers (CSC). These detectors identify muons, provide a fast muon trigger, and give a precise measurement of the muon trajectory. There are 468 six-plane CSCs in the system. The efficiency of finding muon trigger primitives (muon track segments) was studied using 36 CMS CSCs and cosmic ray muons during the Magnet Test and Cosmic Challenge (MTCC) exercise conducted by the CMS experiment in 2006. The efficiency of finding 2-dimensional trigger primitives within 6-layer chambers was found to be 99.93 ± 0.03%.

Muon Measurement in High Field Solenoid Detectors

Muon Measurement in High Field Solenoid Detectors
Title Muon Measurement in High Field Solenoid Detectors PDF eBook
Author Jeffrey B. Rowe
Publisher
Pages 388
Release 1996
Genre
ISBN

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