A search is performed for W' bosons decaying to a top and a bottom quark in the all-hadronic final state, in proton-proton collisions at a center-of-mass energy of 13 TeV. The analyzed data were collected by the CMS experiment between 2016 and 2018 and correspond to an integrated luminosity of 137 fb$^{-1}$. Deep neural network algorithms are used to identify the jet initiated by the bottom quark and the jet containing the decay products of the top quark when the W boson from the top quark decays hadronically. No excess above the estimated standard model background is observed. Upper limits on the production cross sections of W' bosons decaying to a top and a bottom quark are set. Both left- and right-handed W' bosons with masses below 3.4 TeV are excluded at 95% confidence level, and the most stringent limits to date on W' bosons decaying to a top and a bottom quark in the all-hadronic final state are obtained.
The reconstructed m$_{tb}$ distributions in data and expected background in signal region for the data taking period of 2016. Yield in each bin is divided by the corresponding bin width.
The reconstructed m$_{tb}$ distributions in data and expected background in validation region for the data taking period of 2016. Yield in each bin is divided by the corresponding bin width.
The reconstructed m$_{tb}$ distributions in data and expected background in signal region for the data taking period of 2017. Yield in each bin is divided by the corresponding bin width.
A search is performed for pair-produced spin-3/2 excited top quarks ($t^*\bar{t}^*$), each decaying to a top quark and a gluon. The search uses data collected with the CMS detector from pp collisions at a center-of-mass energy of $\sqrt{s}$=8 TeV, selecting events that have a single isolated muon or electron, an imbalance in transverse momentum, and at least six jets, of which one must be compatible with originating from the fragmentation of a b quark. The data, corresponding to an integrated luminosity of 19.5 inverse femtobarns, show no significant excess over standard model predictions, and provide a lower limit of 803 GeV at 95% confidence on the mass of the spin-3/2 t* quark in an extension of the Randall-Sundrum model, assuming a 100% branching fraction of its decay into a top quark and a gluon. This is the first search for a spin-3/2 excited top quark performed at the LHC.
Kinematic distributions of single l + > 5-jet events in data (points), compared to MC simulation normalized to the number of events observed in data. Shown are pT spectra for muons (a) and electrons (b), and jet spectra for the channels $\mu$+jets (c) and e+jets (d). The reconstructed mtg distribution is shown for the $\mu$+jets channel in (e) and for e+jets in (f).
Kinematic distributions of single l + > 5-jet events in data (points), compared to MC simulation normalized to the number of events observed in data. Shown are pT spectra for muons (a) and electrons (b), and jet spectra for the channels $\mu$+jets (c) and e+jets (d). The reconstructed mtg distribution is shown for the $\mu$+jets channel in (e) and for e+jets in (f).
Kinematic distributions of single l + > 5-jet events in data (points), compared to MC simulation normalized to the number of events observed in data. Shown are pT spectra for muons (a) and electrons (b), and jet spectra for the channels $\mu$+jets (c) and e+jets (d). The reconstructed mtg distribution is shown for the $\mu$+jets channel in (e) and for e+jets in (f).
Measurements of $\mathrm{B}^*_\mathrm{s2}(5840)^0$ and $\mathrm{B}_\mathrm{s1}(5830)^0$ mesons are performed using a data sample of proton-proton collisions corresponding to an integrated luminosity of 19.6 fb$^{-1}$, collected with the CMS detector at the LHC at a centre-of-mass energy of 8 TeV. The analysis studies $P$-wave $\mathrm{B}^0_\mathrm{S}$ meson decays into $\mathrm{B}^{(*)+}\mathrm{K}^-$ and $\mathrm{B}^{(*)0}\mathrm{K}^0_\mathrm{S}$, where the $\mathrm{B}^+$ and $\mathrm{B}^0$ mesons are identified using the decays $\mathrm{B}^+\to\mathrm{J}/\psi\,\mathrm{K}^+$ and $\mathrm{B}^0\to\mathrm{J}/\psi\,\mathrm{K}^*(892)^0$. The masses of the $P$-wave $\mathrm{B}^0_\mathrm{S}$ meson states are measured and the natural width of the $\mathrm{B}^*_\mathrm{s2}(5840)^0$ state is determined. The first measurement of the mass difference between the charged and neutral $\mathrm{B}^*$ mesons is also presented. The $\mathrm{B}^*_\mathrm{s2}(5840)^0$ decay to $\mathrm{B}^0\mathrm{K}^0_\mathrm{S}$ is observed, together with a measurement of its branching fraction relative to the $\mathrm{B}^*_\mathrm{s2}(5840)^0\to\mathrm{B}^+\mathrm{K}^-$ decay.
The $\mathrm{J}/\psi\mathrm{K}^+$ invariant mass distribution in data
The $\mathrm{J}/\psi\mathrm{K}^{*0}$ invariant mass distribution in data
The $\mathrm{B}^+\pi^-$ invariant mass distribution of the selected candidates in data
Results are presented from a search for new decaying massive particles whose presence is inferred from an imbalance in transverse momentum and which are produced in association with a single top quark that decays into a bottom quark and two light quarks. The measurement is performed using 19.7 inverse femtobarns of data from proton-proton collisions at a center-of-mass energy of 8 TeV, collected with the CMS detector at the CERN LHC. No deviations from the standard model predictions are observed and lower limits are set on the masses of new invisible bosons. In particular, scalar and vector particles, with masses below 330 and 650 GeV, respectively, are excluded at 95% confidence level, thus substantially extending a previous limit published by the CDF Collaboration.
The invariant mass of the three jets prior to the selection on their mass to be less than 250 GeV, for events with one b-tagged jet. Data are compared to the simulated backgrounds. The expectation from a model for an invisible vector particle with a mass of 700 GeV is represented by the dashed line.
The 95% CL expected and observed CLS limits as functions of the mass of a scalar invisible particle. The expected magnitude of a signal as a function of mass, calculated at leading order, is shown by the dashed curve. The confidence intervals for the expected limit are given at 68% and 95% coverage probability. Information about functional form used for the signal (labeled "scalar signal" in the paper): F = 7.52936*exp(-(0.0070828*(x^1.02681))), where x = M.
The 95% CL expected and observed CLS limits as functions of the mass of a vector invisible particle. The expected magnitude of a signal as a function of mass, calculated at leading order, is shown by the dashed curve. The confidence intervals for the expected limit are given at 68% and 95% coverage probability. Information about functional form used for the signal (labeled "vector signal" in the paper): F = 1390.91*exp(-(0.397971*(x^0.477721))), where x = M.
Searches for anomalous top quark-antiquark production are presented, based on pp collisions at sqrt(s) = 8 TeV. The data, corresponding to an integrated luminosity of 19.7 inverse femtobarns, were collected with the CMS detector at the LHC. The observed ttbar invariant mass spectrum is found to be compatible with the standard model prediction. Limits on the production cross section times branching fraction probe, for the first time, a region of parameter space for certain models of new physics not yet constrained by precision measurements.
Comparison between data and SM prediction for reconstructed M(ttbar) distributions for the boosted semi-leptonic analysis with 0 b-tagged jets.
Comparison between data and SM prediction for reconstructed M(ttbar) distributions for the boosted semi-leptonic analysis with 1 or more b-tagged jets.
Comparison between data and SM prediction for reconstructed M(ttbar) distributions for the all-hadronic analysis.
An exotic narrow state in the $D^0D^0\pi^+$ mass spectrum just below the $D^{*+}D^0$ mass threshold is studied using a data set corresponding to an integrated luminosity of 9 fb$^{-1}$ acquired with the LHCb detector in proton-proton collisions at centre-of-mass energies of 7, 8 and 13 TeV. The state is consistent with the ground isoscalar $T^+_{cc}$ tetraquark with a quark content of $cc\bar{u}\bar{d}$ and spin-parity quantum numbers $\mathrm{J}^{\mathrm{P}}=1^+$. Study of the $DD$ mass spectra disfavours interpretation of the resonance as the isovector state. The decay structure via intermediate off-shell $D^{*+}$ mesons is confirmed by the $D^0\pi^+$ mass distribution. The mass of the resonance and its coupling to the $D^{*}D$ system are analysed. Resonance parameters including the pole position, scattering length, effective range and compositeness are measured to reveal important information about the nature of the $T^+_{cc}$ state. In addition, an unexpected dependence of the production rate on track multiplicity is observed.
Distribution of $D^0 D^0 \pi^+$ mass where the contribution of the non-$D^0$ background has been statistically subtracted. Uncertainties on the data points are statistical only and represent one standard deviation, calculated as a sum in quadrature of the assigned weights from the background-subtraction procedure.
Mass distribution for $D^0 \pi^+$ pairs from selected $D^0 D^0 \pi^+$ candidates with a mass below the $D^{*+}D^0$ mass threshold with non-$D^0$ background subtracted. Uncertainties on the data points are statistical only and represent one standard deviation, calculated as a sum in quadrature of the assigned weights from the background-subtraction procedure.
$D^0 D^0$~mass distributions for selected candidates with the $D^0$ background subtracted. Uncertainties on the data points are statistical only and represent one standard deviation, calculated as a sum in quadrature of the assigned weights from the background-subtraction procedure.
A search for nonresonant excesses in the invariant mass spectra of electron and muon pairs is presented. The analysis is based on data from proton-proton collisions at a center-of-mass energy of 13 TeV recorded by the CMS experiment in 2016, corresponding to a total integrated luminosity of 36 fb$^{-1}$. No significant deviation from the standard model is observed. Limits are set at 95% confidence level on energy scales for two general classes of nonresonant models. For a class of fermion contact interaction models, lower limits ranging from 20 to 32 TeV are set on the characteristic compositeness scale $\Lambda$. For the Arkani-Hamed, Dimopoulos, and Dvali model of large extra dimensions, the first results in the dilepton final state at 13 TeV are reported, and values of the ultraviolet cutoff parameter $\Lambda_\mathrm{T}$ below 6.9 TeV are excluded. A combination with recent CMS diphoton results improves this exclusion to $\Lambda_\mathrm{T}$ below 7.7 TeV, providing the most sensitive limits to date in nonhadronic final states.
A search for the production of heavy partners of the top quark with charge 5/3 is performed in events with a pair of same-sign leptons. The data sample corresponds to an integrated luminosity of 19.5 inverse femtobarns and was collected at sqrt(s) = 8 TeV by the CMS experiment. No significant excess is observed in the data above the expected background and the existence of top-quark partners with masses below 800 GeV is excluded at a 95% confidence level, assuming they decay exclusively to tW. This is the first limit on these particles from the LHC, and it is significantly more restrictive than previous limits.
The distribution of HT for all channels combined after the full selection except for the HT requirement itself.
Expected and observed 95% CL limits on the $\mathrm{T}_{5/3}$ production cross section times the branching fraction for decay to same-sign dileptons.
The distribution of HT for all channels combined, after the requirement of same- sign dileptons, the Z-boson veto, and a requirement of at least two jets.
A search for physics beyond the standard model in the final state with two same-flavour leptons (electrons or muons) and two quarks produced in proton-proton collisions at sqrt(s) = 13 TeV is presented. The data were recorded by the CMS experiment at the CERN LHC and correspond to an integrated luminosity of 2.3 inverse femtobarns. The observed data are in good agreement with the standard model background prediction. The results of the measurement are interpreted in the framework of a recently proposed model in which a heavy Majorana neutrino, N(l), stems from a composite-fermion scenario. Exclusion limits are set for the first time on the mass of the heavy composite Majorana neutrino, m[N(l)], and the compositeness scale Lambda. For the case m[N(l)] = Lambda, the existence of N(e) (N(mu)) is excluded for masses up to 4.60 (4.70) TeV at 95% confidence level.
Results of three searches are presented for the production of supersymmetric particles decaying into final states with missing transverse momentum and exactly two isolated leptons, e or mu. The analysis uses a data sample collected during the first half of 2011 that corresponds to a total integrated luminosity of 1 fb^-1 of sqrt{s} = 7 TeV proton-proton collisions recorded with the ATLAS detector at the Large Hadron Collider. Opposite-sign and same-sign dilepton events are separately studied, with no deviations from the Standard Model expectation observed. Additionally, in opposite- sign events, a search is made for an excess of same-flavour over different-flavour lepton pairs. Effective production cross sections in excess of 9.9 fb for opposite-sign events containing supersymmetric particles with missing transverse momentum greater than 250 GeV are excluded at 95% CL. For same-sign events containing supersymmetric particles with missing transverse momentum greater than 100 GeV, effective production cross sections in excess of 14.8 fb are excluded at 95% CL. The latter limit is interpreted in a simplified weak gaugino production model excluding chargino masses up to 200 GeV.
The dilepton invariant mass distribution for same-sign dileptons.
The missing-mass ET distribution for same-sign dilepton events before any jet requirement.
The missing-mass ET distribution for same-sign dilepton events after requiring two high-pt jets.
Forum