8 research outputs found

    Search for new physics in multijet events with at least one photon and large missing transverse momentum in proton-proton collisions at 13 TeV

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    A search for new physics in final states consisting of at least one photon, multiple jets, and large missing transverse momentum is presented, using proton-proton collision events at a center-of-mass energy of 13 TeV. The data correspond to an integrated luminosity of 137 fb(-1), recorded by the CMS experiment at the CERN LHC from 2016 to 2018. The events are divided into mutually exclusive bins characterized by the missing transverse momentum, the number of jets, the number of b-tagged jets, and jets consistent with the presence of hadronically decaying W, Z, or Higgs bosons. The observed data are found to be consistent with the prediction from standard model processes. The results are interpreted in the context of simplified models of pair production of supersymmetric particles via strong and electroweak interactions. Depending on the details of the signal models, gluinos and squarks of masses up to 2.35 and 1.43 TeV, respectively, and electroweakinos of masses up to 1.23 TeV are excluded at 95% confidence level

    Search for a high-mass dimuon resonance produced in association with b quark jets at sqrt{s} = 13 TeV

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    A search for high-mass dimuon resonance production in association with one or more b quark jets is presented. The study uses proton-proton collision data collected with the CMS detector at the LHC corresponding to an integrated luminosity of 138 fb(-1) at a center-of-mass energy of 13 TeV. Model-independent limits are derived on the number of signal events with exactly one or more than one b quark jet. Results are also interpreted in a lepton-flavor-universal model with Z boson couplings to a bb quark pair (g(b)), an sb quark pair (g(b)delta(bs)), and any same-flavor charged lepton (g(l)) or neutrino pair (g(nu)), with |g(nu)| = |g(l)|. For a Z ' boson with a mass mZ ' = 350 GeV (2 TeV) and |delta(bs)| < 0.25, the majority of the parameter space with 0.0057 < |g(l)| < 0.35 (0.25 < |g(l)| < 0.43) and 0.0079 < |g(b)| < 0.46 (0.34 < |g(b)| < 0.57) is excluded at 95% confidence level. Finally, constraints are set on a Z ' model with parameters consistent with low-energy b -> sll measurements. In this scenario, most of the allowed parameter space is excluded for a Z ' boson with 350 < mZ ' < 500 GeV, while the constraints are less stringent for higher mZ ' hypotheses. This is the first dedicated search at the LHC for a high-mass dimuon resonance produced in association with multiple b quark jets, and the constraints obtained on models with this signature are the most stringent to date

    Publisher Correction: Observation of triple J/ψ meson production in proton-proton collisions

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    In the version of this article initially published, the first affiliation—Yerevan Physics Institute, Yerevan, Armenia—was missing from the list of author affiliations and has now been inserted in the HTML and PDF versions of the articl

    Search for the lepton-flavor violating decay of the Higgs boson and additional Higgs bosons in the eμ final state in proton-proton collisions at s=13  TeV

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    A search for the lepton-flavor violating decay of the Higgs boson and potential additional Higgs bosons with a mass in the range 110-160 GeV to an e±μ∓ pair is presented. The search is performed with a proton-proton collision dataset at a center-of-mass energy of 13 TeV collected by the CMS experiment at the LHC, corresponding to an integrated luminosity of 138 fb−1. No excess is observed for the Higgs boson. The observed (expected) upper limit on the e±μ∓ branching fraction for it is determined to be 4.4 (4.7) × 10−5 at 95% confidence level, the most stringent limit set thus far from direct searches. The largest excess of events over the expected background in the full mass range of the search is observed at an e±μ∓ invariant mass of approximately 146 GeV with a local (global) significance of 3.8 (2.8) standard deviations

    Constraints on anomalous Higgs boson couplings to vector bosons and fermions from the production of Higgs bosons using the <math display="inline"><mi>τ</mi><mi>τ</mi></math> final state

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    International audienceA study of anomalous couplings of the Higgs boson to vector bosons and fermions is presented. The data were recorded by the CMS experiment at a center-of-mass energy of pp collisions at the LHC of 13 TeV and correspond to an integrated luminosity of 138  fb-1. The study uses Higgs boson candidates produced mainly in gluon fusion or electroweak vector boson fusion at the LHC that subsequently decay to a pair of τ leptons. Matrix-element and machine-learning techniques were employed in a search for anomalous interactions. The results are combined with those from the four-lepton and two-photon decay channels to yield the most stringent constraints on anomalous Higgs boson couplings to date. The pure CP-odd scenario of the Higgs boson coupling to gluons is excluded at 2.4 standard deviations. The results are consistent with the standard model predictions

    Probing Small Bjorken- x Nuclear Gluonic Structure via Coherent J/ψ Photoproduction in Ultraperipheral Pb-Pb Collisions at sNN=5.02 TeV

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    Quasireal photons exchanged in relativistic heavy ion interactions are powerful probes of the gluonic structure of nuclei. The coherent J/psi photoproduction cross section in ultraperipheral lead-lead collisions is measured as a function of photon-nucleus center-of-mass energies per nucleon (W-gamma N(Pb)) over a wide range of 40 &lt; W-gamma N(Pb) &lt; 400 GeV. Results are obtained using data at the nucleon-nucleon center-of-mass energy of 5.02 TeV collected by the CMS experiment at the CERN LHC, corresponding to an integrated luminosity of 1.52 nb(-1). The cross section is observed to rise rapidly at low WPb.N, and plateau above W-gamma N(Pb) approximate to 40 GeV, up to 400 GeV, entering a new regime of small Bjorken-x (approximate to 6 x 10(-5)) gluons being probed in a heavy nucleus. The observed energy dependence is not predicted by current quantum chromodynamic models
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