Constraints on models of scalar and vector leptoquarks decaying to a quark and a neutrino at √ s = 13 TeVThe CMS Collaboration * AbstractThe results of a previous search by the CMS Collaboration for squarks and gluinos are reinterpreted to constrain models of leptoquark (LQ) production. The search considers jets in association with a transverse momentum imbalance, using the M T2 variable. The analysis uses proton-proton collision data at √ s = 13 TeV, recorded with the CMS detector at the LHC in 2016 and corresponding to an integrated luminosity of 35.9 fb −1 . Leptoquark pair production is considered with LQ decays to a neutrino and a top, bottom, or light quark. This reinterpretation considers higher mass values than the original CMS search to constrain both scalar and vector LQs. Limits on the cross section for LQ pair production are derived at the 95% confidence level depending on the LQ decay mode. A vector LQ decaying with a 50% branching fraction to tν, and 50% to bτ, has been proposed as part of an explanation of anomalous flavor physics results. In such a model, using only the decays to tν, LQ masses below 1530 GeV are excluded assuming the Yang-Mills case with coupling κ = 1, or 1115 GeV in the minimal coupling case κ = 0, placing the most stringent constraint to date from pair production of vector LQs.Published in Physical Review D as

A search for low mass narrow vector resonances decaying into quark-antiquark pairs is presented. The analysis is based on data collected in 2017 with the CMS detector at the LHC in proton-proton collisions at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 41.1 fb −1. The results of this analysis are combined with those of an earlier analysis based on data collected at the same collision energy in 2016, corresponding to 35.9 fb −1. Signal candidates will be recoiling against initial state radiation and are identified as energetic, large-radius jets with two pronged substructure. The invariant jet mass spectrum is probed for a potential narrow peaking signal over a smoothly falling background. No evidence for such resonances is observed within the mass range of 50-450 GeV. Upper limits at the 95% confidence level are set on the coupling of narrow resonances to quarks, as a function of the resonance mass. For masses between 50 and 300 GeV these are the most sensitive limits to date. This analysis extends the earlier search to a mass range of 300-450 GeV, which is probed for the first time with jet substructure techniques.

Results are reported for the B 0 s → µ + µ − branching fraction and effective lifetime and from a search for the decay B 0 → µ + µ −. The analysis uses a data sample of proton-proton collisions accumulated by the CMS experiment in 2011, 2012, and 2016, with center-of-mass energies (integrated luminosities) of 7 TeV (5 fb −1), 8 TeV (20 fb −1), and 13 TeV (36 fb −1). The branching fractions are determined by measuring event yields relative to B + → J/ψK + decays (with J/ψ → µ + µ −), which results in the reduction of many of the systematic uncertainties. The decay B 0 s → µ + µ − is observed with a significance of 5.6 standard deviations. The branching fraction is measured to be B(B 0 s → µ + µ −) = [2.9 ± 0.7(exp) ± 0.2(frag)] × 10 −9 , where the first uncertainty combines the experimental statistical and systematic contributions, and the second is due to the uncertainty in the ratio of the B 0 s and the B + fragmentation functions. No significant excess is observed for the decay B 0 → µ + µ − , and an upper limit of B(B 0 → µ + µ −) < 3.6 × 10 −10 is obtained at 95% confidence level. The B 0 s → µ + µ − effective lifetime is measured to be τ µ + µ − = 1.70 +0.61 −0.44 ps. These results are consistent with standard model predictions.

A search for phenomena beyond the standard model in final states with two oppositely charged same-flavor leptons and missing transverse momentum is presented. The search uses a data sample of proton-proton collisions at $$ \sqrt{s} $$ s = 13 TeV, corresponding to an integrated luminosity of 137 fb−1, collected by the CMS experiment at the LHC. Three potential signatures of physics beyond the standard model are explored: an excess of events with a lepton pair, whose invariant mass is consistent with the Z boson mass; a kinematic edge in the invariant mass distribution of the lepton pair; and the nonresonant production of two leptons. The observed event yields are consistent with those expected from standard model backgrounds. The results of the first search allow the exclusion of gluino masses up to 1870 GeV, as well as chargino (neutralino) masses up to 750 (800) GeV, while those of the searches for the other two signatures allow the exclusion of light-flavor (bottom) squark masses up to 1800 (1600) GeV and slepton masses up to 700 GeV, respectively, at 95% confidence level within certain supersymmetry scenarios.

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 The CMS collaboration