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Observation of the Production of Three Massive Gauge Bosons at √s=13 TeV
(2020)Physical Review LettersThe first observation is reported of the combined production of three massive gauge bosons (VVV with V = W, Z) in proton-proton collisions at a center-of-mass energy of 13 TeV. The analysis is based on a data sample recorded by the CMS experiment at the CERN LHC corresponding to an integrated luminosity of 137 fb(-1). The searches for individualWWW, WWZ, WZZ, and ZZZ production are performed in final states with three, four, five, and six ...Journal Article -
Reconstruction of signal amplitudes in the CMS electromagnetic calorimeter in the presence of overlapping proton-proton interactions
(2020)Journal of InstrumentationA template fitting technique for reconstructing the amplitude of signals produced by the lead tungstate crystals of the CMS electromagnetic calorimeter is described. This novel approach is designed to suppress the contribution to the signal of the increased number of out-of-time interactions per beam crossing following the reduction of the accelerator bunch spacing from 50 to 25 ns at the start of Run 2 of the LHC. Execution of the algorithm ...Journal Article -
Performance of the CMS Level-1 trigger in proton-proton collisions at √s = 13 TeV
(2020)Journal of InstrumentationAt the start of Run 2 in 2015, the LHC delivered proton-proton collisions at a center-of-mass energy of 13\TeV. During Run 2 (years 2015–2018) the LHC eventually reached a luminosity of 2.1× 1034 cm-2s-1, almost three times that reached during Run 1 (2009–2013) and a factor of two larger than the LHC design value, leading to events with up to a mean of about 50 simultaneous inelastic proton-proton collisions per bunch crossing (pileup). ...Journal Article -
Measurement of CKM matrix elements in single top quark t-channel production in proton-proton collisions at s=13 TeV
(2020)Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy PhysicsThe first direct, model-independent measurement is presented of the modulus of the Cabibbo–Kobayashi–Maskawa (CKM) matrix elements |η|Vtb, |η|Vtd, and |η|Vts, in final states enriched in single top quark t-channel events. The analysis uses proton-proton collision data from the LHC, collected during 2016 by the CMS experiment, at a centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 35.9 fb−1. Processes directly ...Journal Article -
Search for a light pseudoscalar Higgs boson in the boosted μμττ final state in proton-proton collisions at √s = 13 TeV
(2020)Journal of High Energy Physics© 2020, The Author(s). A search for a light pseudoscalar Higgs boson (a) decaying from the 125 GeV (or a heavier) scalar Higgs boson (H) is performed using the 2016 LHC proton-proton collision data at s = 13 TeV, corresponding to an integrated luminosity of 35.9 fb−1, collected by the CMS experiment. The analysis considers gluon fusion and vector boson fusion production of the H, followed by the decay H → aa → μμττ, and considers pseudoscalar ...Journal Article -
Search for resonant pair production of Higgs bosons in the bbZZ channel in proton-proton collisions at √s=13 TeV
(2020)Physical Review DA search for the production of a narrow-width resonance decaying into a pair of Higgs bosons decaying into the bbZZ channel is presented. The analysis is based on data collected with the CMS detector during 2016, in proton-proton collisions at the LHC, corresponding to an integrated luminosity of 35.9 fb(-1). The final states considered are the ones where one of the Z bosons decays into a pair of muons or electrons, and the other Z boson ...Journal Article -
Measurements of (tt)over-barH Production and the CP Structure of the Yukawa Interaction between the Higgs Boson and Top Quark in the Diphoton Decay Channel
(2020)Physical Review LettersThe first observation of the (tt) over barH process in a single Higgs boson decay channel with the full reconstruction of the final state (H -> gamma gamma) is presented, with a significance of 6.6 standard deviations (sigma). The CP structure of Higgs boson couplings to fermions is measured, resulting in an exclusion of the pure CP-odd structure of the top Yukawa coupling at 3.2 sigma. The measurements are based on a sample of protonproton ...Journal Article -
Search for disappearing tracks in proton-proton collisions at s=13TeV
(2020)Physics Letters BA search is presented for long-lived charged particles that decay within the volume of the silicon tracker of the CMS experiment. Such particles can produce events with an isolated track that is missing hits in the outermost layers of the silicon tracker, and is also associated with little energy deposited in the calorimeters and no hits in the muon detectors. The search for events with this “disappearing track” signature is performed in ...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 -
Search for decays of the 125 GeV Higgs boson into a Z boson and a ρ or ϕ meson
(2020)Journal of High Energy PhysicsDecays of the 125 GeV Higgs boson into a Z boson and a ρ0(770) or ϕ(1020) meson are searched for using proton-proton collision data collected by the CMS experiment at the LHC at s = 13 TeV. The analysed data set corresponds to an integrated luminosity of 137 fb−1. Events are selected in which the Z boson decays into a pair of electrons or a pair of muons, and the ρ and ϕ mesons decay into pairs of pions and kaons, respectively. No significant ...Journal Article