Search for long-lived particles using nonprompt jets and missing transverse momentum with proton-proton collisions at root s=13 TeV

A search for long-lived particles decaying to displaced, nonprompt jets and missing transverse momentum is presented. The data sample corresponds to an integrated luminosity of 137 fb(-1) of proton-proton collisions at a center-of-mass energy of 13 TeV collected by the CMS experiment at the CERN LHC in 2016-2018. Candidate signal events containing nonprompt jets are identified using the timing capabilities of the CMS electromagnetic calorimeter. The results of the search are consistent with the background prediction and are interpreted using a gauge-mediated supersymmetry breaking reference model with a gluino next-to-lightest supersymmetric particle. In this model, gluino masses up to 2100, 2500, and 1900 GeV are excluded at 95% confidence level for proper decay lengths of 0.3, 1, and 100 m, respectively. These are the best limits to date for such massive gluinos with proper decay lengths greater than similar to 0.5 m. (C) 2019 The Author. Published by Elsevier B.V

Measurement of the Y(1S) pair production cross section and search for resonances decaying to Y(1S)mu(+)mu(-) in proton-proton collisions at root s=13 TeV

The fiducial cross section for Y(1S) pair production in proton-proton collisions at a center-of-mass energy of 13TeVin the region where both Y(1S) mesons have an absolute rapidity below 2.0 is measured to be 79 +/- 11 (stat) +/- 6 (syst) +/- 3 (B) pbassuming the mesons are produced unpolarized. The last uncertainty corresponds to the uncertainty in the Y(1S) meson dimuon branching fraction. The measurement is performed in the final state with four muons using proton-proton collision data collected in 2016 by the CMS experiment at the LHC, corresponding to an integrated luminosity of 35.9 fb(-1). This process serves as a standard model reference in a search for narrow resonances decaying to Y(1S)mu(+)mu(-) in the same final state. Such a resonance could indicate the existence of a tetraquark that is a bound state of two bquarks and two (b) over bar antiquarks. The tetraquark search is performed for masses in the vicinity of four times the bottom quark mass, between 17.5 and 19.5 GeV, while a generic search for other resonances is performed for masses between 16.5 and 27 GeV. No significant excess of events compatible with a narrow resonance is observed in the data. Limits on the production cross section times branching fraction to four muons via an intermediate Y(1S) resonance are set as a function of the resonance mass. (C) 2020 The Author(s). Published by Elsevier B.V

Search for anomalous electroweak production of vector boson pairs in association with two jets in proton-proton collisions at 13 TeV

A search for anomalous electroweak production of WW, WZ, and ZZ boson pairs in association with two jets in proton-proton collisions at root s = 13 TeV at the LHC is reported. The data sample corresponds to an integrated luminosity of 35.9 fb(-1) collected with the CMS detector. Events are selected by requiring two jets with large rapidity separation and invariant mass, one or two leptons (electrons or muons), and a W or Z boson decaying hadronically. No excess of events with respect to the standard model background predictions is observed and constraints on the structure of quartic vector boson interactions in the framework of dimension-8 effective field theory operators are reported. Stringent limits on parameters of the effective field theory operators are obtained. The observed 95% confidence level limits for the S0, M0, and T0 operators are -2.7 < f(S0)/A(4) < 2.7, -1.0 < f(M0)/A(4) < 1.0, and -0.17 < f(T0)/A(4) < 0.16, in units of TeV-4. Constraints are also reported on the product of the cross section and branching fraction for vector boson fusion production of charged Higgs bosons as a function of mass from 600 to 2000 GeV. The results are interpreted in the context of the Georgi-Machacek model. (C) 2019 The Author(s). Published by Elsevier B.V