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Probing Charm Quark Dynamics via Multiparticle Correlations in Pb-Pb Collisions at root √sNN=5.02 TeV
(2022)Physical Review LettersMultiparticle azimuthal correlations of prompt D-0 mesons arc measured in Pb-Pb collisions at a nucleon-nucleon center-of-mass energy of root s(NN) = 5.02 TeV. For the first time, a four-particle cumulant method is used to extract the second Fourier coefficient of the azimuthal distribution (v(2)) of D-0 mesons as a function of event centrality and the D-0 transverse momentum. The ratios of the four-particle v(2) values to previously ...Journal Article -
Search for resonances decaying to three W bosons in the hadronic final state in proton-proton collisions at ps=13 TeV
(2022)Physical Review DA search for Kaluza-Klein excited vector boson resonances, WKK, decaying in cascade to three W bosons via a scalar radion R, WKK → WR → WWW, in a final state containing two or three massive jets is presented. The search is performed with ffiffi s p ¼ 13 TeV proton-proton collision data collected by the CMS experiment at the CERN LHC during 2016–2018, corresponding to an integrated luminosity of 138 fb−1. Two final states are simultaneously ...Journal Article -
Observation of the Bc+ Meson in Pb-Pb and pp Collisions at √sNN=5.02 TeV and Measurement of its Nuclear Modification Factor
(2022)Physical Review LettersThe Bc+ meson is observed for the first time in heavy ion collisions. Data from the CMS detector are used to study the production of the Bc+ meson in lead-lead (Pb-Pb) and proton-proton (pp) collisions at a center-of-mass energy per nucleon pair of sNN=5.02 TeV, via the Bc+→(J/ψ→μ+μ-)μ+νμ decay. The Bc+ nuclear modification factor, derived from the Pb-Pb-to-pp ratio of production cross sections, is measured in two bins of the trimuon ...Journal Article -
Precision luminosity measurement in proton–proton collisions at √s = 13 TeV in 2015 and 2016 at CMS
(2021)The European Physical Journal CThe measurement of the luminosity recorded by the CMS detector installed at LHC interaction point 5, using proton–proton collisions at √s = 13 TeV in 2015 and 2016, is reported. The absolute luminosity scale is measured for individual bunch crossings using beam-separation scans (the van der Meer method), with a relative precision of 1.3 and 1.0% in 2015 and 2016, respectively. The dominant sources of uncertainty are related to residual ...Journal Article -
Measurement of the associated production of a Z boson with charm or bottom quark jets in proton-proton collisions at root s=13 TeV
(2020)Physical Review DRatios of cross sections, sigma(Z + c jets)/sigma(Z + jets), sigma(Z + b jets)/sigma(Z + jets), and sigma(Z + c jets)/sigma(Z + b jets) in the associated production of a Z boson with at least one charm or bottom quark jet are measured in proton-proton collisions at root s = 13 TeV. The data sample, collected by the CMS experiment at the CERN LHC, corresponds to an integrated luminosity of 35.9 fb(-1), with a fiducial volume of p(T) > 30 ...Journal Article -
Study of central exclusive π+π− production in proton-proton collisions at √s=5.02 and 13TeV
(2020)The European Physical Journal CCentral exclusive and semiexclusive production of π+π− pairs is measured with the CMS detector in proton-proton collisions at the LHC at center-of-mass energies of 5.02 and 13 TeV. The theoretical description of these nonperturbative processes, which have not yet been measured in detail at the LHC, poses a significant challenge to models. The two pions are measured and identified in the CMS silicon tracker based on specific energy loss, ...Journal Article -
Mixed higher-order anisotropic flow and nonlinear response coefficients of charged particles in PbPb collisions at root s(NN)=2.76 and 5.02 TeV
(2020)The European Physical Journal CAnisotropies in the initial energy density distribution of the quark-gluon plasma created in high energy heavy ion collisions lead to anisotropies in the azimuthal distributions of the final-state particles known as collective anisotropic flow. Fourier harmonic decomposition is used to quantify these anisotropies. The higher-order harmonics can be induced by the same order anisotropies (linear response) or by the combined influence of ...Journal Article -
Measurement of the cross section for electroweak production of a Z boson, a photon and two jets in proton-proton collisions at √s = 13 TeV and constraints on anomalous quartic couplings
(2020)Journal of High Energy PhysicsA measurement is presented of the cross section for electroweak production of a Z boson and a photon in association with two jets (Zγjj) in proton-proton collisions. The Z boson candidates are selected through their decay into a pair of electrons or muons. The process of interest, electroweak Zγjj production, is isolated by selecting events with a large dijet mass and a large pseudorapidity gap between the two jets. The measurement is ...Journal Article -
Identification of heavy, energetic, hadronically decaying particles using machine-learning techniques
(2020)Journal of InstrumentationMachine-learning (ML) techniques are explored to identify and classify hadronic decays of highly Lorentz-boosted W/Z/Higgs bosons and top quarks. Techniques without ML have also been evaluated and are included for comparison. The identification performances of a variety of algorithms are characterized in simulated events and directly compared with data. The algorithms are validated using proton-proton collision data at root S = 13 TeV, ...Journal Article -
Search for new neutral Higgs bosons through the H → ZA → ℓ+ℓ−bb¯ process in pp collisions at s√= 13 TeV
(2020)Journal of High Energy PhysicsThis paper reports on a search for an extension to the scalar sector of the standard model, where a new CP-even (odd) boson decays to a Z boson and a lighter CP-odd (even) boson, and the latter further decays to a b quark pair. The Z boson is reconstructed via its decays to electron or muon pairs. The analysed data were recorded in proton-proton collisions at a center-of-mass energy s√ = 13 TeV, collected by the CMS experiment at the LHC ...Journal Article