169 research outputs found
Author Correction: A portrait of the Higgs boson by the CMS experiment ten years after the discovery
No full textIn 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 articl
Search for medium effects using jets from bottom quarks in PbPb collisions at <tex>\sqrt{s_{NN}}$</tex>=5.02 TeV
No full textAbstract: The first study of the shapes of jets arising from bottom (b) quarks in heavy ion collisions is presented. Jet shapes are studied using charged hadron constituents as a function of their radial distance from the jet axis. Lead-lead (PbPb) collision data at a nucleon-nucleon center-of-mass energy of root s(NN)= 5.02 TeV were recorded by the CMS detector at the LHC, with an integrated luminosity of 1.69nb(-1). Compared to proton-proton collisions, aredistribution of the energy inbjets to larger distances from the jet axis is observed in PbPb collisions. This medium-induced redistribution is found to be substantially larger forbjets than for inclusive jets. (c) 2023 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). Funded by SCOAP(3)
Measurement of the B-s(0) \u2192 mu(+)mu(-) decay properties and search for the B-0 \u2192 mu(+)mu(-) decay in proton-proton collisions at 1as=13 TeV
No full textAbstract: Measurements are presented of the B0s & RARR; & mu;+& mu;- branching fraction and effective lifetime, as well as results of a search for the B0 & RARR; & mu;+& mu;- decay in proton-proton collisions at & RADIC;s =13 TeV at the LHC. The analysis is based on data collected with the CMS detector in 2016-2018 corresponding to an integrated luminosity of 140 fb-1. The branching fraction of the B0s & RARR; & mu;+& mu;- decay and the effective B0s meson lifetime are the most precise single measurements to date. No evidence for the B0 & RARR; & mu;+& mu;- decay has been found. All results are found to be consistent with the standard model predictions and previous measurements. & COPY; 2023 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons .org /licenses /by /4 .0/). Funded by SCOAP3
Search for the Higgs boson decay to a pair of electrons in proton-proton collisions at 1as=13 TeV
No full textAbstract: A search is presented for the Higgs boson decay to a pair of electrons (e(+)e(-)) in proton-proton collisions at root s= 13 TeV. The data set was collected with the CMS experiment at the LHC between 2016 and 2018, corresponding to an integrated luminosity of 138fb(-1). The analysis uses event categories targeting Higgs boson production via gluon fusion and vector boson fusion. The observed upper limit on the Higgs boson branching fraction to an electron pair is 3.0 x 10(-4) (3.0 x 10(-4) expected) at the 95% confidence level, which is the most stringent limit on this branching fraction to date. (c) 2023 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)
Observation of four top quark production in proton-proton collisions at s=13TeV
No full textThe observation of the production of four top quarks in proton-proton collisions is reported, based on a data sample collected by the CMS experiment at a center-of-mass energy of 13 TeV in 2016–2018 at the CERN LHC and corresponding to an integrated luminosity of 138fb−1. Events with two same-sign, three, or four charged leptons (electrons and muons) and additional jets are analyzed. Compared to previous results in these channels, updated identification techniques for charged leptons and jets originating from the hadronization of b quarks, as well as a revised multivariate analysis strategy to distinguish the signal process from the main backgrounds, lead to an improved expected signal significance of 4.9 standard deviations above the background-only hypothesis. Four top quark production is observed with a significance of 5.6 standard deviations, and its cross section is measured to be 17.7−3.5+3.7(stat)−1.9+2.3(syst)fb, in agreement with the available standard model predictions. © 2023 The Author(s
Search for dark matter particles in W+ W− events with transverse momentum imbalance in proton-proton collisions at √s = 13 TeV
No full textA search for dark matter particles is performed using events with a pair of W bosons and large missing transverse momentum. Candidate events are selected by requiring one or two leptons (l = electrons or muons). The analysis is based on proton-proton collision data collected at a center-of-mass energy of 13 TeV by the CMS experiment at the LHC and corresponding to an integrated luminosity of 138 fb−1. No significant excess over the expected standard model background is observed in the lνqq and 2l2ν final states of the W+W− boson pair. Limits are set on dark matter production in the context of a simplified dark Higgs model, with a dark Higgs boson mass above the W+W− mass threshold. The dark matter phase space is probed in the mass range 100–300 GeV, extending the scope of previous searches. Current exclusion limits are improved in the range of dark Higgs masses from 160 to 250 GeV, for a dark matter mass of 200 GeV. © The Author(s) 2024
Search for nonresonant Higgs boson pair production in final state with two bottom quarks and two tau leptons in proton-proton collisions at 1as=13 TeV
No full textAbstract: A search for the nonresonant production of Higgs boson pairs (HH) via gluon-gluon and vector boson fusion processes in final states with two bottom quarks and two tau leptons is presented. The search uses data from proton-proton collisions at a center-of-mass energy of & RADIC;s = 13 TeV recorded with the CMS detector at the LHC, corresponding to an integrated luminosity of 138 fb-1. Events in which at least one tau lepton decays hadronically are considered and multiple machine learning techniques are used to identify and extract the signal. The data are found to be consistent, within uncertainties, with the standard model (SM) predictions. Upper limits on the HH production cross section are set to constrain the parameter space for anomalous Higgs boson couplings. The observed (expected) upper limit at 95% confidence level corresponds to 3.3 (5.2) times the SM prediction for the inclusive HH cross section and to 124 (154) times the SM prediction for the vector boson fusion HH cross section. At 95% confidence level, the Higgs field self-coupling is constrained to be within -1.7 and 8.7 times the SM expectation, and the coupling of two Higgs bosons to two vector bosons is constrained to be within -0.4 and 2.6 times the SM expectation. & COPY; 2022 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons .org /licenses /by /4 .0/). Funded by SCOAP3
Search for pair-produced vector-like leptons in final states with third-generation leptons and at least three b quark jets in proton-proton collisions at 1as=13 TeV
No full textAbstract: The first search is presented for vector-like leptons (VLLs) in the context of the "4321 model", an ultraviolet-complete model with the potential to explain existing B physics measurements that are in tension with standard model predictions. The analyzed data, corresponding to an integrated luminosity of 96.5 fb-1, were recorded in 2017 and 2018 with the CMS detector at the LHC in proton-proton collisions at root s = 13 TeV. Final states with >= 3 b-tagged jets and two third-generation leptons (tau tau, tau nu tau, or nu tau nu tau) are considered. Upper limits are derived on the VLL production cross section in the VLL mass range 500-1050 GeV. The maximum likelihood fit prefers the presence of signal at the level of 2.8 standard deviations, for a representative VLL mass point of 600 GeV. As a consequence, the observed upper limits are approximately double the expected limits. (c) 2023 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons .org /licenses /by /4 .0/). Funded by SCOAP3
Search for a heavy composite Majorana neutrino in events with dilepton signatures from proton-proton collisions at 1as=13 TeV
No full textAbstract: Results are presented of a search for a heavy Majorana neutrino N \u2803 decaying into two same-flavor leptons \u2803 (electrons or muons) and a quark-pair jet. A model is considered in which the N \u2803 is an excited neutrino in a compositeness scenario. The analysis is performed using a sample of proton-proton collisions at & RADIC;s = 13 TeV recorded by the CMS experiment at the CERN LHC, corresponding to an integrated luminosity of 138 fb-1. The data are found to be in agreement with the standard model prediction. For the process in which the N \u2803 is produced in association with a lepton, followed by the decay of the N \u2803 to a same-flavor lepton and a quark pair, an upper limit at 95% confidence level on the product of the cross section and branching fraction is obtained as a function of the N \u2803 mass mN \u2803 and the compositeness scale \u2804. For this model the data exclude the existence of Ne (N & mu;) for mN \u2803 below 6.0 (6.1) TeV, at the limit where mN \u2803 is equal to \u2804. For mN \u2803 N 1 TeV, values of \u2804 less than 20 (23) TeV are excluded. These results represent a considerable improvement in sensitivity, covering a larger parameter space than previous searches in pp collisions at 13 TeV.& COPY; 2023 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons .org /licenses /by /4 .0/). Funded by SCOAP3
Measurement of the t(t)over-bar charge asymmetry in events with highly Lorentz-boosted in collisions at 1as=13 TeV
No full textAbstract: The measurement of the charge asymmetry in top quark pair events with highly Lorentz-boosted top quarks decaying to a single lepton and jets is presented. The analysis is performed using protonproton collisions at root s = 13 TeV with the CMS detector at the LHC and corresponding to an integrated luminosity of 138 fb(-1). The selection is optimized for top quarks produced with large Lorentz boosts, resulting in nonisolated leptons and overlapping jets. The top quark charge asymmetry is measured for events with a t (t) over bar invariant mass larger than 750 GeV and corrected for detector and acceptance effects using a binned maximum likelihood fit. The measured top quark charge asymmetry of (0.42(-0.69)(+0.64))% is in good agreement with the standard model prediction at next-to-next-to-leading order in quantum chromodynamic perturbation theory with next-to-leading-order electroweak corrections. The result is also presented for two invariant mass ranges, 750-900 and >900 GeV. (c) 2023 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)
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