Search for a low-mass tau(-)tau(+) resonance in association with a bottom quark in proton-proton collisions at root s=13 TeV

A general search is presented for a low-mass (-+) resonance produced in association with a bottom quark. The search is based on proton-proton collision data at a center-of-mass energy of 13 TeV collected by the CMS experiment at the LHC, corresponding to an integrated luminosity of 35.9 fb(-1). The data are consistent with the standard model expectation. Upper limits at 95% confidence level on the cross section times branching fraction are determined for two signal models: a light pseudoscalar Higgs boson decaying to a pair of leptons produced in association with bottom quarks, and a low-mass boson X decaying to a -lepton pair that is produced in the decay of a bottom-like quark B such that B bX. Masses between 25 and 70 GeV are probed for the light pseudoscalar boson with upper limits ranging from 250 to 44 pb. Upper limits from 20 to 0.3 pb are set on B masses between 170 and 450 GeV for X boson masses between 20 and 70 GeV

Constraints on anomalous HVV couplings from the production of Higgs bosons decaying to τ lepton pairs

A study is presented of anomalous HVV interactions of the Higgs boson, including its CP properties. The study uses Higgs boson candidates produced mainly in vector boson fusion and gluon fusion that subsequently decay to a pair of tau leptons. The data were recorded by the CMS experiment at the LHC in 2016 at a center-of-mass energy of 13 TeV and correspond to an integrated luminosity of 35.9 fb(-1). A matrix element technique is employed for the analysis of anomalous interactions. The results are combined with those from the H -> 4l decay channel presented earlier, yielding the most stringent constraints on anomalous Higgs boson couplings to electroweak vector bosons expressed as effective cross section fractions and phases: the CP-violating parameter f(a3) cos(phi(a3)) = (0.00 +/- 0.27) x 10(-3) and the CP-conserving parameters f(a2) cos(phi(a2)) = (0.08)(-0.21)(+1.04)) x 10(-3), f(Lambda 1) cos(phi(Lambda 1)) = (0.00)(-0.09)(+0.53)) x 10(-3), and f(Lambda 1)(Z gamma) cos(phi(Z gamma)(Lambda 1)) = (0.0(-1.3)(+1.1)) x 10(-3). The current dataset does not allow for precise constraints on CP properties in the gluon fusion process. The results are consistent with standard model expectations

Search for W boson decays to three charged pions

For the first time, a search for the rare decay of the W boson to three charged pions has been performed. Proton-proton collision data recorded by the CMS experiment at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 77.3 fb$^{; ; ; -1}; ; ;$, have been analyzed. No significant excess is observed above the background expectation. An upper limit of 1.01 $\times$ 10$^{; ; ; -6}; ; ;$ is set at 95% confidence level on the branching fraction of the W boson to three charged pions. This provides a strong motivation for theoretical calculations of this branching fraction

Search for MSSM Higgs bosons decaying to mu(+)mu(-) in proton-proton collisions at root s=13TeV

A search is performed for neutral non-standard-model Higgs bosons decaying to two muons in the context of the minimal supersymmetric standard model (MSSM). Proton-proton collision data recorded by the CMS experiment at the CERN Large Hadron Collider at a center-of-mass energy of 13 TeV were used, corresponding to an integrated luminosity of 35.9 fb(-1). The search is sensitive to neutral Higgs bosons produced via the gluon fusion process or in association with a b (b) over bar quark pair. No significant deviations from the standard model expectation are observed. Upper limits at 95% confidence level are set in the context of the m(h)(mod+) and phenomenological MSSM scenarios on the parameter tan beta as a function of the mass of the pseudoscalar A boson, in the range from 130 to 600 GeV. The results are also used to set a model-independent limit on the product of the branching fraction for the decay into a muon pair and the cross section for the production of a scalar neutral boson, either via gluon fusion, or in association with b quarks, in the mass range from 130 to 1000 GeV

Combination of CMS searches for heavy resonances decaying to pairs of bosons or leptons

A statistical combination of searches for heavy resonances decaying to pairs of bosons or leptons is presented. The data correspond to an integrated luminosity of 35.9 fb$^{; ; ; -1}; ; ;$ collected during 2016 by the CMS experiment at the LHC in proton-proton collisions at a center-of-mass energy of 13 TeV. The data are found to be consistent with expectations from the standard model background. Exclusion limits are set in the context of models of spin-1 heavy vector triplets and of spin-2 bulk gravitons. For mass-degenerate W' and Z' resonances that predominantly couple to the standard model gauge bosons, the mass exclusion at 95% confidence level of heavy vector bosons is extended to 4.5 TeV as compared to 3.8 TeV determined from the best individual channel. This excluded mass increases to 5.0 TeV if the resonances couple predominantly to fermions

Observation of forward neutron multiplicity dependence of dimuon acoplanarity in ultraperipheral Pb-Pb collisions at √sNN=5.02 TeV

The 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, were 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 extracted for events including 0, 1, or at least 2 neutrons detected in the forward pseudorapidity range |η|>8.3. The back-to-back correlation structure from leading-order photon-photon scattering is found to be significantly broader for events with a larger number of emitted neutrons from each nucleus, corresponding to interactions with a smaller impact parameter. This observation provides a data- driven demonstration that the average transverse momentum of photons emitted from relativistic heavy ions has an impact parameter dependence. These results provide new constraints on models of photon-induced interactions in ultraperipheral collisions. They also provide a baseline to search for possible final-state effects on lepton pairs caused by traversing a quark-gluon plasma produced in hadronic heavy ion collisions

Measurements of production cross sections of polarized same-sign W boson pairs in association with two jets in proton-proton collisions at s√= 13 TeV

The first measurements of production cross sections of polarized same-sign W±W± boson pairs in proton-proton collisions are reported. The measurements are based on a data sample collected with the CMS detector at the LHC at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 137 fb−1. Events are selected by requiring exactly two same-sign leptons, electrons or muons, moderate missing transverse momentum, and two jets with a large rapidity separation and a large dijet mass to enhance the contribution of same-sign W±W± scattering events. An observed (expected) 95% confidence level upper limit of 1.17 (0.88) fb is set on the production cross section for longitudinally polarized same-sign W±W± boson pairs. The electroweak production of same-sign W±W± boson pairs with at least one of the W bosons longitudinally polarized is measured with an observed (expected) significance of 2.3 (3.1) standard deviations

Measurements of pp→ZZ production cross sections and constraints on anomalous triple gauge couplings at √s=13 TeV

The 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 for events with two pairs of opposite-sign, same-flavor leptons produced in the mass region 60 < m(l+l-) < 120 GeV is consistent with standard model predictions. Differential cross sections are also measured and agree with theoretical predictions. The invariant mass distribution of the four- lepton system is used to set limits on anomalous ZZZ and ZZ gamma couplings

Evidence for Higgs boson decay to a pair of muons

Evidence for Higgs boson decay to a pair of muons is presented. This result combines searches in four exclusive categories targeting the production of the Higgs boson via gluon fusion, via vector boson fusion, in association with a vector boson, and in association with a top quark-antiquark pair. The analysis is performed using proton-proton collision data at $\sqrt{;s}; =$ 13 TeV, corresponding to an integrated luminosity of 137 fb$^{;-1};$, recorded by the CMS experiment at the CERN LHC. An excess of events over the background expectation is observed in data with a significance of 3.0 standard deviations, where the expectation for the standard model (SM) Higgs boson with mass of 125.38 GeV is 2.5. The combination of this result with that from data recorded at $\sqrt{;s}; =$ 7 and 8 TeV, corresponding to integrated luminosities of 5.1 and 19.7 fb$^{;-1};$, respectively, increases both the expected and observed significances by 1%. The measured signal strength, relative to the SM prediction, is 1.19 $^{;+0.40};_{;-0.39};$ (stat) $^{;+0.15};_{;-0.14};$ (syst). This result constitutes the first evidence for the decay of the Higgs boson to second generation fermions and is the most precise measurement of the Higgs boson coupling to muons reported to date

Constraints on the initial state of Pb-Pb collisions via measurements of Z-boson yields and azimuthal anisotropy at √sNN=5.02 TeV

The 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 collision. Yields of Z bosons are compared to Glauber model predictions and are found to deviate from these expectations in peripheral collisions, indicating the presence of initial collision geometry and centrality selection effects. The precision of the measurement allows, for the first time, for a data-driven determination of the nucleon-nucleon integrated luminosity as a function of lead-lead centrality, thereby eliminating the need for its estimation based on a Glauber model