Search for new physics in the multijet and missing transverse momentum final state in proton-proton collisions at √s=8 Tev

Peer reviewe

Relative Modification of Prompt psi(2S) and J/psi Yields from pp to PbPb Collisions at root(S)(NN)=5.02 TeV

Peer reviewe

Development of the CMS detector for the CERN LHC Run 3

A 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

Muon identification using multivariate techniques in the CMS experiment in proton-proton collisions at sqrt(s) = 13 TeV

An 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

Evidence for the 125 GeV Higgs boson decaying to a pair of tau leptons

A search for a standard model Higgs boson decaying into a pair of τ leptons is performed using events recorded by the CMS experiment at the LHC in 2011 and 2012. The dataset corresponds to an integrated luminosity of 4.9 fb-1 at a centre-of-mass energy of 7TeV and 19.7fb-1 at 8TeV. Each τ lepton decays hadronically or leptonically to an electron or a muon, leading to six different final states for the τ-lepton pair, all considered in this analysis. An excess of events is observed over the expected background contributions, with a local significance larger than 3 standard deviations for mH values between 115 and 130 GeV. The best fit of the observed H → ττ signal cross section times branching fraction for mH = 125 GeV is 0.78±0.27 times the standard model expectation. These observations constitute evidence for the 125 GeV Higgs boson decaying to a pair of τ leptons

Search for new physics in the multijet and missing transverse momentum final state in proton-proton collisions at root s=8 Tev

A search for new physics is performed in multijet events with large missing transverse momentum produced in proton-proton collisions at √s = 8 TeV using a data sample corresponding to an integrated luminosity of 19.5 fb -1 collected with the CMS detector at the LHC. The data sample is divided into three jet multiplicity categories (3-5, 6-7, and ≥8 jets), and studied further in bins of two variables: the scalar sum of jet transverse momenta and the missing transverse momentum. The observed numbers of events in various categories are consistent with backgrounds expected from standard model processes. Exclusion limits are presented for several simplified supersymmetric models of squark or gluino pair production. [Figure not available: see fulltext.] © 2014 The Author(s)

Determination of the top-quark pole mass and strong coupling constant from the t(t)over-bar production cross section in pp collisions at root s=7 TeV

The inclusive cross section for top-quark pair production measured by the CMS experiment in proton-proton collisions at a center-of-mass energy of 7 TeV is compared to the QCD prediction at next-to-next-to-leading order with various parton distribution functions to determine the top-quark pole mass, mtpole, or the strong coupling constant, αS. With the parton distribution function set NNPDF2.3, a pole mass of 176. 7+3.8-3.4 GeV is obtained when constraining αS at the scale of the Z boson mass, mZ, to the current world average. Alternatively, by constraining mtpole to the latest average from direct mass measurements, a value of αS(mZ) = 0. 1151+0.0033-0.0032 is extracted. This is the first determination of αS using events from top-quark production. © 2013 The Authors. Published by Elsevier B.V