9 research outputs found

    Search for a high-mass dimuon resonance produced in association with b quark jets at 1as=13 TeV

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    Abstract: 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)| 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

    Measurements of inclusive and differential cross sections for the Higgs boson production and decay to four-leptons in proton-proton collisions at 1as=13 TeV

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    Abstract: Measurements of the inclusive and differential fiducial cross sections for the Higgs boson production in the H -> ZZ -> 4 l ( l = e, mu) decay channel are presented. The results are obtained from the analysis of proton-proton collision data recorded by the CMS experiment at the CERN LHC at a center-of-mass energy of 13TeV, corresponding to an integrated luminosity of 138 fb(-1). The measured inclusive fiducial cross section is 2.73 +/- 0.26 fb, in agreement with the standard model expectation of 2.86 +/- 0.1 fb. Differential cross sections are measured as a function of several kinematic observables sensitive to the Higgs boson production and decay to four leptons. A set of double-differential measurements is also performed, yielding a comprehensive characterization of the four leptons final state. Constraints on the Higgs boson trilinear coupling and on the bottom and charm quark coupling modifiers are derived from its transverse momentum distribution. All results are consistent with theoretical predictions from the standard model

    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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    Abstract: 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 high-mass exclusive \u3b3\u3b3 \u2192 WW and \u3b3\u3b3 \u2192 ZZ production in proton-proton collisions at 1as=13 TeV

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    Abstract: A search is performed for exclusive high-mass gamma gamma -> WW and gamma gamma -> ZZ production in proton-proton collisions using intact forward protons reconstructed in near-beam detectors, with both weak bosons decaying into boosted and merged jets. The analysis is based on a sample of proton-proton collisions collected by the CMS and TOTEM experiments at root s = 13 TeV, corresponding to an integrated luminosity of 100 fb(-1). No excess above the standard model background prediction is observed, and upper limits are set on the pp -> pWWp and pp -> pZZp cross sections in a fiducial region defined by the diboson invariant mass m(VV) > 1 TeV (with V = W, Z) and proton fractional momentum loss 0.04 < xi < 0.20. The results are interpreted as new limits on dimension-6 and dimension-8 anomalous quartic gauge couplings

    Measurement of the Dependence of the Hadron Production Fraction Ratios f_{s}/f_{u} and f_{d}/f_{u} on B Meson Kinematic Variables in Proton-Proton Collisions at sqrt[s]=13  TeV

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    : The dependence of the ratio between the B_{s}^{0} and B^{+} hadron production fractions, f_{s}/f_{u}, on the transverse momentum (p_{T}) and rapidity of the B mesons is studied using the decay channels B_{s}^{0}→J/ψϕ and B^{+}→J/ψK^{+}. The analysis uses a data sample of proton-proton collisions at a center-of-mass energy of 13&nbsp;TeV, collected by the CMS experiment in 2018 and corresponding to an integrated luminosity of 61.6  fb^{-1}. The f_{s}/f_{u} ratio is observed to depend on the B p_{T} and to be consistent with becoming asymptotically constant at large p_{T}. No rapidity dependence is observed. The ratio of the B^{0} to B^{+} meson production fractions, f_{d}/f_{u}, is also measured, for the first time in proton-proton collisions, using the B^{0}→J/ψK^{*0} decay channel. The result is found to be within 1 standard deviation of unity and independent of p_{T} and rapidity, as expected from isospin invariance

    Search for exotic Higgs boson decays H \u2192 AA \u2192 4\u3b3 with events containing two merged diphotons in proton-proton collisions at 1as=13 TeV

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    Abstract: We present the first direct search for exotic Higgs boson decays H -> AA, A -> gamma gamma in events with two photonlike objects. The hypothetical particle A is a low-mass spin-0 particle decaying promptly to a merged diphoton reconstructed as a single photonlike object. We analyze the data collected by the CMS ffiffi experiment at V s = 13 TeV corresponding to an integrated luminosity of 136 fb-1. No excess above the estimated background is found. We set upper limits on the branching fraction B(H -> AA -> 4 gamma) of (0.9-3.3) x 10-3 at 95% confidence level for masses of A in the range 0.1-1.2 GeV

    Measurement of the dependence of the hadron production fraction ratios <i>f<sub>s</sub></i>/<i>f<sub>u</sub></i> and <i>f<sub>d</sub></i>/<i>f<sub>u</sub></i> on <i>B</i> meson kinematic variables in proton-proton collisions at 1a<i>s</i>=13 TeV

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    Abstract: The dependence of the ratio between the B-s(0) and B+ hadron production fractions, f(s)/f(u), on the transverse momentum (p(T)) and rapidity of the B mesons is studied using the decay channels B-s(0) -> J/psi phi and B+ -> J/psi K+. The analysis uses a data sample of proton-proton collisions at a center-of-mass energy of 13 TeV, collected by the CMS experiment in 2018 and corresponding to an integrated luminosity of 61.6 fb(-1). The f(s)/f(u) ratio is observed to depend on the B p(T) and to be consistent with becoming asymptotically constant at large p(T). No rapidity dependence is observed. The ratio of the B-0 to B+ meson production fractions, f(d)/f(u), is also measured, for the first time in proton-proton collisions, using the B-0 -> J/psi K*(0) decay channel. The result is found to be within 1 standard deviation of unity and independent of p(T) and rapidity, as expected from isospin invariance

    Observation of \u3c4 Lepton Pair Production in Ultraperipheral Pb-Pb Collisions at <tex>\sqrt{s_{NN}}$</tex>=5.02 TeV

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    Abstract: We present an observation of photon-photon production of t lepton pairs in ultraperipheral lead-lead collisions. The measurement is based on a data sample with an integrated luminosity of 404 mu b(-1) collected by the CMS experiment at a center-of-mass energy per nucleon pair of root s(NN) = 5.02 TeV. The gamma gamma -> tau(+)tau(-) process is observed for tau(+)tau(-) events with a muon and three charged hadrons in the final state. The measured fiducial cross section is sigma(gamma gamma ->tau(+)tau(-)) = 4.8 +/- 0.6(stat) +/- 0.5(syst) mu b, where the second (third) term corresponds to the statistical (systematic) uncertainty in sigma(gamma gamma ->tau(+)tau(-)) in agreement with leading-order QED predictions. Using sigma(gamma gamma ->tau(+)tau(-)), we estimate a model-dependent value of the anomalous magnetic moment of the t lepton of at a(tau) = 0.001(-0.089)(+0.055)
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