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Measurement of the top quark Yukawa coupling from t t ¯ kinematic distributions in the dilepton final state in proton-proton collisions at s =13 TeV
(2020)Physical Review DA measurement of the Higgs boson Yukawa coupling to the top quark is presented using proton-proton collision data at √s=13 TeV, corresponding to an integrated luminosity of 137 fb−1, recorded with the CMS detector. The coupling strength with respect to the standard model value, Yt, is determined from kinematic distributions in t¯t final states containing ee, μμ, or eμ pairs. Variations of the Yukawa coupling strength lead to modified ...Journal Article -
MUSiC: a model-unspecific search for new physics in proton–proton collisions at √s=13TeV
(2021)The European Physical Journal CResults of the Model Unspecific Search in CMS (MUSiC), using proton–proton collision data recorded at the LHC at a centre-of-mass energy of 13TeV, corresponding to an integrated luminosity of 35.9fb-1, are presented. The MUSiC analysis searches for anomalies that could be signatures of physics beyond the standard model. The analysis is based on the comparison of observed data with the standard model prediction, as determined from simulation, ...Journal Article -
Constraints on the Initial State of Pb-Pb Collisions via Measurements of Z-Boson Yields and Azimuthal Anisotropy at sNN =5.02 TeV
(2021)Physical Review LettersThe CMS experiment at the LHC has measured the differential cross sections of Z bosons decaying to pairs of leptons, as functions of transverse momentum and rapidity, in lead-lead collisions at a nucleon-nucleon center-of-mass energy of 5.02 TeV. The measured Z boson elliptic azimuthal anisotropy coefficient is compatible with zero, showing that Z bosons do not experience significant final-state interactions in the medium produced in the ...Journal Article -
Constraints on the χc1 versus χc2 Polarizations in Proton-Proton Collisions at √s=8 TeV
(2020)Physical Review LettersThe polarizations of promptly produced χc1 and χc2 mesons are studied using data collected by the CMS experiment at the LHC, in proton-proton collisions at √s=8 TeV. The χc states are reconstructed via their radiative decays χc→J/ψγ, with the photons being measured through conversions to e+e−, which allows the two states to be well resolved. The polarizations are measured in the helicity frame, through the analysis of the χc2 to χc1 yield ...Journal Article -
Measurements of pp→ZZ production cross sections and constraints on anomalous triple gauge couplings at √s=13TeV
(2021)The European Physical Journal CThe production of Z boson pairs in proton-proton (pp) collisions, pp -> (Z/gamma*)(Z/gamma*) -> 2l2l', where l, l' = e or mu, is studied at a center-of-mass energy of 13 TeV with the CMS detector at the CERN LHC. The data sample corresponds to an integrated luminosity of 137 fb(-1), collected during 2016-2018. The ZZ production cross section, sigma(tot)(pp -> ZZ) = 17.4 +/- 0.3 (stat) +/- 0.5 (syst) +/- 0.4 (theo)+/- 0.3 (lumi) pb, measured ...Journal Article -
Measurements of angular distance and momentum ratio distributions in three-jet and Z + two-jet final states in pp collisions
(2021)The European Physical Journal CCollinear (small-angle) and large-angle, as well as soft and hard radiations are investigated in three-jet and Z + two-jet events collected in proton-proton collisions at the LHC. The normalized production cross sections are measured as a function of the ratio of transverse momenta of two jets and their angular separation. The measurements in the three-jet and Z + two-jet events are based on data collected at a center-of-mass energy of ...Journal Article -
The very forward CASTOR calorimeter of the CMS experiment
(2021)Journal of InstrumentationThe physics motivation, detector design, triggers, calibration, alignment, simulation, and overall performance of the very forward CASTOR calorimeter of the CMS experiment are reviewed. The CASTOR Cherenkov sampling calorimeter is located very close to the LHC beam line, at a radial distance of about 1 cm from the beam pipe, and at 14.4 m from the CMS interaction point, covering the pseudorapidity range of -6.6 < eta < - 5.2. It was ...Journal Article -
Measurement of the azimuthal anisotropy of Υ(1S)and Υ(2S)mesons in PbPb collisions at √sNN=5.02 TeV
(2021)Physics Letters BThe second-order Fourier coefficients (v2) characterizing the azimuthal distributions of [Formula presented] and [Formula presented] mesons produced in PbPb collisions at sNN=5.02TeV are studied. The [Formula presented] mesons are reconstructed in their dimuon decay channel, as measured by the CMS detector. The collected data set corresponds to an integrated luminosity of 1.7nb−1. The scalar product method is used to extract the v2 ...Journal Article -
Measurement of prompt D0 and D‾0 meson azimuthal anisotropy and search for strong electric fields in PbPb collisions at sNN=5.02TeV
(2021)Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy PhysicsThe strong Coulomb field created in ultrarelativistic heavy ion collisions is expected to produce a rapidity-dependent difference (Δv2) in the second Fourier coefficient of the azimuthal distribution (elliptic flow, v2) between D0 (u‾c) and D‾0 (uc‾) mesons. Motivated by the search for evidence of this field, the CMS detector at the LHC is used to perform the first measurement of Δv2. The rapidity-averaged value is found to be ...Journal Article -
Observation of Forward Neutron Multiplicity Dependence of Dimuon Acoplanarity in Ultraperipheral Pb-Pb Collisions at sNN=5.02 TeV
(2021)Physical Review LettersThe first measurement of the dependence of γγ→μ+μ− production on the multiplicity of neutrons emitted very close to the beam direction in ultraperipheral heavy ion collisions is reported. Data for lead-lead interactions at √sNN=5.02 TeV, with an integrated luminosity of approximately 1.5 nb−1, are collected using the CMS detector at the LHC. The azimuthal correlations between the two muons in the invariant mass region 8<mμμ<60 GeV are ...Journal Article