The measurements of the inclusive and differential fiducial cross sections of the Higgs boson decaying to a pair of photons are presented. The analysis is performed using proton-proton collisions data recorded with the CMS detector at the LHC at a centre-of-mass energy of 13 TeV and corresponding to an integrated luminosity of 137 fb$^{-1}$. The inclusive fiducial cross section is measured to be $\sigma_\mathrm{fid}$ = 73.4 $_{-5.3}^{+5.4}$ (stat) ${}_{-2.2}^{+2.4}$ (syst) fb, in agreement with the standard model expectation of 75.4 $\pm$ 4.1 fb. The measurements are also performed in fiducial regions targeting different production modes and as function of several observables describing the diphoton system, the number of additional jets present in the event, and other kinematic observables. Two double differential measurements are performed. No significant deviations from the standard model expectations are observed.
Differential fiducial higgs to diphoton cross section with respect to $p_{\mathrm{T}}^{\gamma\gamma}$. The last bin in the differential observable extends to infinity and the measured fiducial cross section in this bin is devided by the given bin width
Differential fiducial higgs to diphoton cross section with respect to $p_{\mathrm{T}}^{\gamma\gamma}$. The last bin in the differential observable extends to infinity and the measured fiducial cross section in this bin is devided by the given bin width
Correlation between the measured fiducial cross sections in the different bins of $p_{\mathrm{T}}^{\gamma\gamma}$
Results are presented from a search for CP violation in top quark pair production, using proton-proton collisions at a center-of-mass energy of 13 TeV. The data used for this analysis consist of final states with two charged leptons collected by the CMS experiment, and correspond to an integrated luminosity of 35.9 fb$^{-1}$. The search uses two observables, $\mathcal{O}_1$ and $\mathcal{O}_3$, which are Lorentz scalars. The observable $\mathcal{O}_1$ is constructed from the four-momenta of the charged leptons and the reconstructed top quarks, while $\mathcal{O}_3$ consists of the four-momenta of the charged leptons and the b quarks originating from the top quarks. Asymmetries in these observables are sensitive to CP violation, and their measurement is used to determine the chromoelectric dipole moment of the top quark. The results are consistent with the expectation from the standard model.
Measured asymmetries of O_1 and O_3 with statistical uncertainties
The measured asymmetries of O_1 and O_3, and dimensionless CEDM \ImdtG, extracted using the asymmetries in O_1 and O_3, with their uncertainties.
Results for the covariance matrix where the parameters a and b are taken from a linear fit (equation 11) to the different CP-violating samples (CEMD).
Results are presented on a search for CP violation in the production and decay of top quark-antiquark pairs in the lepton+jets channel. The search is based on data from proton-proton collisions at 13 TeV, collected with the CMS detector, corresponding to an integrated luminosity of 138 fb$^{-1}$. Possible CP violation effects are evaluated by measuring uncorrected asymmetries in observables constructed from linearly independent four-momentum vectors of the final-state particles. The dimensionless chromoelectric dipole moment of the top quark obtained from the observed asymmetries is measured to be 0.04 $\pm$ 0.10 (stat) $\pm$ 0.07 (syst), and the asymmetries exhibit no evidence for CP-violating effects, consistent with expectations from the standard model.
Proton-proton interactions resulting in final states with two photons are studied in a search for the signature of flavor-changing neutral current interactions of top quarks (t) and Higgs bosons (H). The analysis is based on data collected at a center-of-mass energy of 13 TeV with the CMS detector at the LHC, corresponding to an integrated luminosity of 137 fb$^{-1}$. No significant excess above the background prediction is observed. Upper limits on the branching fractions ($\mathcal{B}$) of the top quark decaying to a Higgs boson and an up (u) or charm quark (c) are derived through a binned fit to the diphoton invariant mass spectrum. The observed (expected) 95% confidence level upper limits are found to be 0.019 (0.031)% for $\mathcal B$(t $\to$ Hu) and 0.073 (0.051)% for $\mathcal{B}$(t $\to$ Hc). These are the strictest upper limits yet determined.
Expected and observed 95\% CL upper limits on the branching fraction of the top quark decaying to the Higgs boson and a light-flavor quark (either an up or a charm quark)
A search for the exotic decay of the Higgs boson to a pair of light pseudoscalars, each of which subsequently decays into a pair of photons, is presented. The search uses data from proton-proton collisions at $\sqrt{s}$ = 13 TeV recorded with the CMS detector at the LHC that corresponds to an integrated luminosity of 132 fb$^{-1}$. The analysis probes pseudoscalar bosons with masses in the range 15-62 GeV, coming from the Higgs boson decay, which leads to four well-isolated photons in the final state. No significant deviation from the background-only hypothesis is observed. Upper limits are set on the product of the Higgs boson production cross section and branching fraction into four photons. The observed (expected) limits range from 0.80 (1.00) fb for a pseudoscalar boson mass of 15 GeV to 0.26 (0.24) fb for a mass of 62 GeV at 95% confidence level.
Exclusion limits on the product of the production cross section and the branching fraction, as a function of the pseudoscalar mass hypothesis.
The structure of nucleons is multidimensional and depends on the transverse momenta, spatial geometry, and polarization of the constituent partons. Such a structure can be studied using high-energy photons produced in ultraperipheral heavy-ion collisions. The first measurement of the azimuthal angular correlations of exclusively produced events with two jets in photon-lead interactions at large momentum transfer is presented, a process that is considered to be sensitive to the underlying nuclear gluon polarization. This study uses a data sample of ultraperipheral lead-lead collisions at $\sqrt{s_\mathrm{NN}}$ = 5.02 TeV, corresponding to an integrated luminosity of 0.38 nb$^{-1}$, collected with the CMS experiment at the LHC. The measured second harmonic of the correlation between the sum and difference of the two jet momenta is found to be positive, and rising, as the dijet momentum increases. A well-tuned model that has been successful at describing a wide range of proton scattering data from the HERA experiments fails to describe the observed correlations, suggesting the presence of gluon polarization effects.
The unfolded 1/${N_{\mathrm{events}}} dN/d\Phi$ distribution
The unfolded $<\cos(2\Phi)>$ distribution as a function of $Q_{\mathrm{T}}$
A search is reported for heavy resonances and quantum black holes decaying into e$\mu$, e$\tau$, and $\mu\tau$ final states in proton-proton collision data recorded by the CMS experiment at the CERN LHC during 2016-2018 at $\sqrt{s}$ = 13 TeV, corresponding to an integrated luminosity of 138 fb$^{-1}$. The e$\mu$, e$\tau$, and $\mu\tau$ invariant mass spectra are reconstructed, and no evidence is found for physics beyond the standard model. Upper limits are set at 95% confidence level on the product of the cross section and branching fraction for lepton flavor violating signals. Three benchmark signals are studied: resonant $\tau$ sneutrino production in $R$ parity violating supersymmetric models, heavy Z' gauge bosons with lepton flavor violating decays, and nonresonant quantum black hole production in models with extra spatial dimensions. Resonant $\tau$ sneutrinos are excluded for masses up to 4.2 TeV in the e$\mu$ channel, 3.7 TeV in the e$\tau$ channel, and 3.6 TeV in the $\mu\tau$ channel. A Z' boson with lepton flavor violating couplings is excluded up to a mass of 5.0 TeV in the e$\mu$ channel, up to 4.3 TeV in the e$\tau$ channel, and up to 4.1 TeV in the $\mu\tau$ channel. Quantum black holes in the benchmark model are excluded up to the threshold mass of 5.6 TeV in the e$\mu$ channel, 5.2 TeV in the e$\tau$ channel, and 5.0 TeV in the $\mu\tau$ channel. In addition, model-independent limits are extracted to allow comparisons with other models for the same final states and similar event selection requirements. The results of these searches provide the most stringent limits available from collider experiments for heavy particles that undergo lepton flavor violating decays.
Mass distributions for the e$\mu$ channel. In addition to the observed data (black points) and SM prediction (filled histograms), expected signal distributions for three models are shown: the RPV SUSY model with $\lambda = \lambda' = 0.01$ and $\tau$ sneutrino mass of 1.6 TeV, a Z′ boson ($\mathcal{B}=0.1$) with a mass of 1.6 TeV , and the QBH signal expectation for $n=4$ and a threshold mass of 1.6 TeV. The bin width gradually increases with mass.
Mass distributions for the e$\tau$ channel. In addition to the observed data (black points) and SM prediction (filled histograms), expected signal distributions for three models are shown: the RPV SUSY model with $\lambda = \lambda' = 0.01$ and $\tau$ sneutrino mass of 1.6 TeV, a Z′ boson ($\mathcal{B}=0.1$) with a mass of 1.6 TeV , and the QBH signal expectation for $n=4$ and a threshold mass of 1.6 TeV. The bin width gradually increases with mass.
Mass distributions for the $\mu\tau$ channel. In addition to the observed data (black points) and SM prediction (filled histograms), expected signal distributions for three models are shown: the RPV SUSY model with $\lambda = \lambda' = 0.01$ and $\tau$ sneutrino mass of 1.6 TeV, a Z′ boson ($\mathcal{B}=0.1$) with a mass of 1.6 TeV , and the QBH signal expectation for $n=4$ and a threshold mass of 1.6 TeV. The bin width gradually increases with mass.
A search is presented for vector-like T and B quark-antiquark pairs produced in proton-proton collisions at a center-of-mass energy of 13 TeV. Data were collected by the CMS experiment at the CERN LHC in 2016-2018, with an integrated luminosity of 138 fb$^{-1}$. Events are separated into single-lepton, same-sign charge dilepton, and multilepton channels. In the analysis of the single-lepton channel a multilayer neural network and jet identification techniques are employed to select signal events, while the same-sign dilepton and multilepton channels rely on the high-energy signature of the signal to distinguish it from standard model backgrounds. The data are consistent with standard model background predictions, and the production of vector-like quark pairs is excluded at 95% confidence level for T quark masses up to 1.54 TeV and B quark masses up to 1.56 TeV, depending on the branching fractions assumed, with maximal sensitivity to decay modes that include multiple top quarks. The limits obtained in this search are the strongest limits to date for $\mathrm{T\overline{T}}$ production, excluding masses below 1.48 TeV for all decays to third generation quarks, and are the strongest limits to date for $\mathrm{B\overline{B}}$ production with B quark decays to tW.
Distribution of ST in the training region for the $T\overline{T}$ MLP. The observed data are shown along with the predicted $T\overline{T}$ signal with mass of 1.2 (1.5) TeV in the singlet scenario and the background. Statistical and systematic uncertainties in the background prediction before performing the fit to data are also shown. The signal predictions of 1.2 TeV and 1.5 TeV signals have been scaled by factors of x300 and x600, respectively, for visibility.
Distribution of the leading jet’s DEEPAK8 light quark or gluon score in the training region for the $T\overline{T}$ MLP. The observed data are shown along with the predicted $T\overline{T}$ signal with mass of 1.2 (1.5) TeV in the singlet scenario and the background. Statistical and systematic uncertainties in the background prediction before performing the fit to data are also shown. The signal predictions of 1.2 TeV and 1.5 TeV signals have been scaled by factors of x300 and x600, respectively, for visibility.
Distribution of the MLP T quark score in the SR for the $T\overline{T}$ search. The observed data, predicted $T\overline{T}$ signal with mass of 1.2 (1.5) TeV in the singlet scenario, and the background are all shown. Statistical and systematic uncertainties in the background prediction before performing the fit to data are also shown. The signal predictions of 1.2 TeV and 1.5 TeV signals have been scaled by factors of x10 and x20, respectively, for visibility.
Results are presented from a search for the Higgs boson decay H $\to$ Z$\gamma$, where Z $\to$$\ell^+\ell^-$ with $\ell$ = e or $\mu$. The search is performed using a sample of proton-proton (pp) collision data at a center-of-mass energy of 13 TeV, recorded by the CMS experiment at the LHC, corresponding to an integrated luminosity of 138 fb$^{-1}$. Events are assigned to mutually exclusive categories, which exploit differences in both event topology and kinematics of distinct Higgs production mechanisms to enhance signal sensitivity. The signal strength $\mu$, defined as the product of the cross section and the branching fraction [$\sigma($pp $\to$ H$)\mathcal{B}($H $\to$ Z$\gamma)$] relative to the standard model prediction, is extracted from a simultaneous fit to the $\ell^+\ell^-\gamma$ invariant mass distributions in all categories and is found to be $\mu$ = 2.4 $\pm$ 0.9 for a Higgs boson mass of 125.38 GeV. The statistical significance of the observed excess of events is 2.7 standard deviations. This measurement corresponds to $\sigma($pp $\to$ H$)\mathcal{B}($H $\to$ Z$\gamma)$ = 0.21 $\pm$ 0.08 pb. The observed (expected) upper limit at 95% confidence level on $\mu$ is 4.1 (1.8). The ratio of branching fractions $\mathcal{B}($H $\to$ Z$\gamma) / \mathcal{B}($H $\to$ $\gamma\gamma)$ is measured to be 1.5 $^{+0.7}_{-0.6}$, which agrees with the standard model prediction of 0.69 $\pm$ 0.04 at the 1.5 standard deviation level.
The $\mathcal{D}_{\mathrm{VBF}}$ distributions for signal, simulated background, and data. The $\mathcal{D}_{\mathrm{VBF}}$ distribution includes only dijet-tagged events. The sum of contributions from all signal production mechanisms is shown by the blue line, while the contribution from only the VBF mechanism is shown by the red line. The uncertainty band incorporates all statistical and systematic uncertainties in the expected background. The dashed lines indicate the boundaries for dijet-tagged categories.
The $\mathcal{D}_{\mathrm{kin}}$ distributions for signal, simulated background, and data. The $\mathcal{D}_{\mathrm{kin}}$ distribution includes only untagged events. The sum of contributions from all signal production mechanisms is shown by the blue line. The uncertainty band incorporates all statistical and systematic uncertainties in the expected background. The dashed lines indicate the boundaries for untagged categories. The gray shaded region in the $\mathcal{D}_{\mathrm{kin}}$ distribution is excluded from the analysis.
Fits to the $m_{\ell^+\ell^-\gamma}$ data distribution in the lepton-tagged categories. In the upper panel, the red solid line shows the result of a signal-plus-background fit to the given category. The red dashed line shows the background component of the fit. The green and yellow bands represent the 68 and 95% CL uncertainties in the fit. Also plotted is the expected SM signal, scaled by a factor of 10. In the lower panel, the data minus the background component of the fit is shown.
The path-length dependent parton energy loss within the dense partonic medium created in lead-lead collisions at a nucleon-nucleon center-of-mass energy of $\sqrt{s_\mathrm{NN}}$ = 5.02 TeV is studied by determining the azimuthal anisotropies for dijets with high transverse momentum. The data were collected by the CMS experiment in 2018 and correspond to an integrated luminosity of 1.69 nb$^{-1}$. For events containing back-to-back jets, correlations in relative azimuthal angle and pseudorapidity ($\eta$) between jets and hadrons, and between two hadrons, are constructed. The anisotropies are expressed as the Fourier expansion coefficients $v_n$, $n = $ 2-4 of these azimuthal distributions. The dijet $v_n$ values are extracted from long-range (1.5 $\lt$$\vert\Delta\eta\vert$$\lt$ 2.5) components of these correlations, which suppresses the background contributions from jet fragmentation processes. Positive dijet $v_2$ values are observed which increase from central to more peripheral events, while the $v_3$ and $v_4$ values are consistent with zero within experimental uncertainties.
The dijet $v_{n}$ data points factorized using different associated hadron pT bins for 0-10 % centrality bin. The data points are corrected for the jet reconstruction bias effects.
The dijet $v_{n}$ data points factorized using different associated hadron pT bins for 10-30 % centrality bin. The data points are corrected for the jet reconstruction bias effects.
The dijet $v_{n}$ data points factorized using different associated hadron pT bins for 30-50 % centrality bin. The data points are corrected for the jet reconstruction bias effects.