A search for heavy, long-lived, charged particles with large ionization energy loss within the silicon tracker of the CMS experiment is presented. A data set of proton-proton collisions at a center of mass energy at $\sqrt{s}$ = 13 TeV, collected in 2017 and 2018 at the CERN LHC, corresponding to an integrated luminosity of 101 fb$^{-1}$, is used in this analysis. Two different approaches for the search are taken. A new method exploits the independence of the silicon pixel and strips measurements, while the second method improves on previous techniques using ionization to determine a mass selection. No significant excess of events above the background expectation is observed. The results are interpreted in the context of the pair production of supersymmetric particles, namely gluinos, top squarks, and tau sleptons, and of the Drell-Yan pair production of fourth generation ($\tau'$) leptons with an electric charge equal to or twice the absolute value of the electron charge ($e$). An interpretation of a Z$'$ boson decaying to two $\tau'$ leptons with an electric charge equal to 2$e$ is presented for the first time. The 95% confidence upper limits on the production cross section are extracted for each of these hypothetical particles.
The $F_{\text{i}}^{\text{Pixels}}$ vs $G_{\text{i}}^{\text{Strips}}$ distribution for the SM MC after passing the selection criteria listed in Table 2.
The $F_{\text{i}}^{\text{Pixels}}$ vs $G_{\text{i}}^{\text{Strips}}$ distribution the 1800 GeV mass gluino R-hadron (right), after passing the selection criteria listed in Table 2.
The $G_{\text{i}}^{\text{Strips}}$ distribution in the FAIL region for events passing the event selection and with $55 < p_{\mathrm{T}} < 200$ GeV.
A first measurement is presented of the cross section for the scattering of same-sign W boson pairs via the detection of a $\tau$ lepton. The data from proton-proton collisions at the center-of-mass energy of 13 TeV were collected by the CMS detector at the LHC, and correspond to an integrated luminosity of 138 fb$^{-1}$. Events were selected that contain two jets with large pseudorapidity and large invariant mass, one $\tau$ lepton, one light lepton (e or $\mu$), and significant missing transverse momentum. The measured cross section for electroweak same-sign WW scattering is 1.44$^{+0.63}_{-0.56}$ times the standard model prediction. In addition, a search is presented for the indirect effects of processes beyond the standard model via the effective field theory framework, in terms of dimension-6 and dimension-8 operators.
Measured signal strength for electroweak (EW) same-sign WW scattering in events with one tau lepton and one light lepton (electron or muon), as well as two jets with large pseudorapidity separation and large dijet invariant mass. The signal strength is defined as the ratio of the observed yield to the Standard Model prediction.
Measured signal strength for combined electroweak (EW) and QCD same-sign WW scattering in events with one tau lepton and one light lepton (electron or muon), as well as two jets with large pseudorapidity separation and large dijet invariant mass. The signal strength is defined as the ratio of the observed yield to the Standard Model prediction.
Observed and expected 68% and 95% confidence intervals on the Wilson coefficients associated with the EFT dimension-6 operators.
We present an analysis based on models of the intrinsic transverse momentum of partons in nucleons by studying the dilepton transverse momentum in Drell-Yan events. Using parameter tuning in event generators and existing data from fixed-target experiments, from the Tevatron, and from the LHC, our investigation spans three orders of magnitude in center-of-mass energy and two orders of magnitude in dilepton invariant mass. The results show an energy-scaling behavior of the intrinsic transverse momentum parameters, independent of the dilepton invariant mass at a given center-of-mass energy.
Tuned intrinsic kT parameters BeamRemnants:PrimordialkThard in Pythia with the underlying-event tune CP5 at nucleon-nucleon center-of-mass energy from 38.8 GeV to 13 TeV.
Tuned intrinsic kT parameters BeamRemnants:PrimordialkThard in Pythia with the underlying-event tune CP4 at nucleon-nucleon center-of-mass energy from 38.8 GeV to 13 TeV.
Tuned intrinsic kT parameters BeamRemnants:PrimordialkThard in Pythia with the underlying-event tune CP3 at nucleon-nucleon center-of-mass energy from 38.8 GeV to 13 TeV.
A measurement of the Higgs boson mass and width via its decay to two Z bosons is presented. Proton-proton collision data collected by the CMS experiment, corresponding to an integrated luminosity of 138 fb$^{-1}$ at a center-of-mass energy of 13 TeV is used. The invariant mass distribution of four leptons in the on-shell Higgs boson decay is used to measure its mass and contrain its width. This yields the most precise single measurement of the Higgs boson mass to date, 125.04 $\pm$ 0.12 GeV, and an upper limit on the width $\Gamma_\mathrm{H}$$\lt$ 330 MeV at 95% confidence level. A combination of the on- and off-shell Higgs boson production decaying to four leptons is used to determine the Higgs boson width, assuming that no new virtual particles affect the production, a premise that is tested by adding new heavy particles in the gluon fusion loop model. This result is combined with a previous CMS analysis of the off-shell Higgs boson production with decay to two leptons and two neutrinos, giving a measured Higgs boson width of 3.0$^{+2.0}_{-1.5}$ MeV, in agreement with the standard model prediction of 4.1 MeV. The strength of the off-shell Higgs boson production is also reported. The scenario of no off-shell Higgs boson production is excluded at a confidence level corresponding to 3.8 standard deviations.
Observed profile likelihood projection on mH, for different flavor categories combined, using the N-2D′ VXBS approach. Both statistical and systematic uncertainties have been considered.
Observed profile likelihood projection on mH, for the 4mu final state, using the N-2D′ VXBS approach. Both statistical and systematic uncertainties have been considered.
Observed profile likelihood projection on mH, for the 4e final state, using the N-2D′ VXBS approach. Both statistical and systematic uncertainties have been considered.
Measurements of the polarization and spin correlation in top quark pairs ($\mathrm{t\bar{t}}$) are presented using events with a single electron or muon and jets in the final state. The measurements are based on proton-proton collision data from the LHC at $\sqrt{s}$ = 13 TeV collected by the CMS experiment, corresponding to an integrated luminosity of 138 fb$^{-1}$. All coefficients of the polarization vectors and the spin correlation matrix are extracted simultaneously by performing a binned likelihood fit to the data. The measurement is performed inclusively and in bins of additional observables, such as the mass of the $\mathrm{t\bar{t}}$ system and the top quark scattering angle in the $\mathrm{t\bar{t}}$ rest frame. The measured polarization and spin correlation are in agreement with the standard model. From the measured spin correlation, conclusions on the $\mathrm{t\bar{t}}$ spin entanglement are drawn by applying the Peres-Horodecki criterion. The standard model predicts entangled spins for $\mathrm{t\bar{t}}$ states at the production threshold and at high masses of the $\mathrm{t\bar{t}}$ system. Entanglement is observed for the first time in events at high $\mathrm{t\bar{t}}$ mass, where a large fraction of the $\mathrm{t\bar{t}}$ decays are space-like separated, with an expected and observed significance of above 5 standard deviations.
Results for full matrix measurement inclusive from $m(t\bar{t})$
Covariance for full matrix measurement inclusive from $m(t\bar{t})$
Results for full matrix measurement all bins from $m(t\bar{t})$ fit
A search for light long-lived particles decaying to displaced jets is presented, using a data sample of proton-proton collisions at a center-of-mass energy of 13.6 TeV, corresponding to an integrated luminosity of 34.7 fb$^{-1}$, collected with the CMS detector at the CERN LHC in 2022. Novel trigger, reconstruction, and machine-learning techniques were developed for and employed in this search. After all selections, the observations are consistent with the background predictions. Limits are presented on the branching fraction of the Higgs boson to long-lived particles that subsequently decay to quark pairs or tau lepton pairs. An improvement by up to a factor of 10 is achieved over previous limits for models with long-lived particle masses smaller than 60 GeV and proper decay lengths smaller than 1 m. The first constraints are placed on the fraternal twin Higgs and folded supersymmetry models, where the lower bounds on the top quark partner mass reach up to 350 GeV for the fraternal twin Higgs model and 250 GeV for the folded supersymmetry model.
The predicted background yields and the number of observed events for the data with $g_{\mathrm{prompt-veto}}>0.985$, shown for different bins of the displacd-dijet GNN score $g_{\mathrm{displaced}}$. Expected signal yields for the $\mathrm{H \to SS}$, $\mathrm{S \to b\overline{b}}$ signature are also shown for models with $m_{\mathrm{S}}=40~\mathrm{GeV}$, and $c \tau_{0}=1$, $10$ or $100\mathrm{mm}$, assuming a branching fraction of $1\%$ for the $\mathrm{H \to SS}$ decay.
The 95% CL upper limits on the branching fraction $\mathcal{B}(\mathrm{H \to SS})$ with $\mathrm{S \to b\overline{b}}$ deacy, for different LLP masses $m_{\mathrm{S}}$ and proper decay lengths $c\tau_{0}$.
The 95% CL upper limits on the branching fraction $\mathcal{B}(\mathrm{H \to SS})$ with $\mathrm{S \to d\overline{d}}$ decay, for different LLP masses $m_{\mathrm{S}}$ and proper decay lengths $c\tau_{0}$.
The first measurement of the inclusive and normalised differential cross sections of single top quark production in association with a W boson in proton-proton collisions at a centre-of-mass energy of 13.6 TeV is presented. The data were recorded with the CMS detector at the LHC in 2022, and correspond to an integrated luminosity of 34.7 fb$^{-1}$. The analysed events contain one muon and one electron in the final state. For the inclusive measurement, multivariate discriminants exploiting the kinematic properties of the events are used to separate the signal from the dominant top quark-antiquark production background. A cross section of 82.3 $\pm$ 2.1 (stat) ${}^{+9.9}_{-9.7}$ (syst) $\pm$ 3.3 (lumi) pb is obtained, consistent with the predictions of the standard model. A fiducial region is defined according to the detector acceptance to perform the differential measurements. The resulting differential distributions are unfolded to particle level and show good agreement with the predictions at next-to-leading order in perturbative quantum chromodynamics.
The distribution of the RF output for events in the 1j1b region. The number of observed events (points) and estimated signal and background events (filled histograms) from the maximum likelihood fit are shown. The vertical bars on the points represent the statistical uncertainty in the data, and the hatched band the total uncertainty in the estimated events after the fit. The lower panels display the ratio of the data to the sum of the estimated events (points) after the fit, with the bands giving the corresponding uncertainties.
The distribution of the RF output for events in the 2j1b region. The number of observed events (points) and estimated signal and background events (filled histograms) from the maximum likelihood fit are shown. The vertical bars on the points represent the statistical uncertainty in the data, and the hatched band the total uncertainty in the estimated events after the fit. The lower panels display the ratio of the data to the sum of the estimated events (points) after the fit, with the bands giving the corresponding uncertainties.
The distribution of the Subleading jet $p_{T}$ for events in the 2j2b region. The number of observed events (points) and estimated signal and background events (filled histograms) from the maximum likelihood fit are shown. The vertical bars on the points represent the statistical uncertainty in the data, and the hatched band the total uncertainty in the estimated events after the fit. The lower panels display the ratio of the data to the sum of the estimated events (points) after the fit, with the bands giving the corresponding uncertainties.
The forward-backward asymmetry in Drell-Yan production and the effective leptonic electroweak mixing angle are measured in proton-proton collisions at $\sqrt{s}$ = 13 TeV, collected by the CMS experiment and corresponding to an integrated luminosity of 138 fb$^{-1}$. The measurement uses both dimuon and dielectron events, and is performed as a function of the dilepton mass and rapidity. The unfolded angular coefficient $A_4$ is also extracted, as a function of the dilepton mass and rapidity. Using the CT18Z set of parton distribution functions, we obtain $\sin\theta^\ell_\text{eff}$ = 0.23157 $\pm$ 0.00031, where the uncertainty includes the experimental and theoretical contributions. The measured value agrees with the standard model fit result to global experimental data. This is the most precise $\sin\theta^\ell_\text{eff}$ measurement at a hadron collider, with a precision comparable to the results obtained at LEP and SLD.
Measured $A_4(|Y|,M))$ distribution for the combined Run 2 data.
Correlation coefficients for the $A_4(|Y|,M)$ values among different $|Y|-M$ bins. The $A_4(|Y|,M)$ values and total uncertainties are shown in Figure 8 in the paper.
This Letter presents the first search for bottom quark associated production of the standard model Higgs boson, in final states with leptons. Higgs boson decays to pairs of tau leptons and pairs of leptonically decaying W bosons are considered. The search is performed using data collected from 2016 to 2018 by the CMS experiment in proton-proton collisions at a centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 138 fb${-1}$. Upper limits at the 95% confidence level are placed on the signal strength for Higgs boson production in association with bottom quarks; the observed (expected) upper limit is 3.7 (6.1) times the standard model prediction.
Inclusive signal strength modifiers $\mu$.
Cross section limits assuming a SM cross-section of 1.489 pb $\sigma_i$.
Signal strength modifier calculated for the bbH(yb2) process $\mu_i$.
A measurement of the ratio of branching fractions $R$(J/$\psi$) = $\mathcal{B}$(B$^+_\text{c}$$\to$ J/$\psi$$\tau^+\nu_\tau$)/$\mathcal{B}$(B$^+_\text{c}$$\to$ J/$\psi$$\mu^+\nu_\mu$) in the J/$\psi$$\to$$\mu^+\mu^-$, $\tau^+$$\to$$\mu^+\mu_\tau\overline{\nu}_\tau$ decay channel is presented. This measurement uses a sample of proton-proton collision data collected at a center-of-mass energy of 13 TeV by the CMS experiment in 2018, corresponding to an integrated luminosity of 59.7 fb$^{-1}$. The measured ratio, $R$(J/$\psi$) = 0.17$^{+ 0.18}_{- 0.17}$ (stat) $^{+ 0.21}_{- 0.22}$ (syst) $^{+ 0.19}_{- 0.18}$ (theo) = 0.17 $\pm$ 0.33, agrees with the value of 0.2582 $\pm$ 0.0038 predicted by the standard model, which assumes lepton flavor universality.
Measured R(J/psi) ratio