The first observation of top quark production in proton-nucleus collisions is reported using proton-lead data collected by the CMS experiment at the CERN LHC at a nucleon-nucleon center-of-mass energy of sqrt(s[NN]) = 8.16 TeV. The measurement is performed using events with exactly one isolated electron or muon and at least four jets. The data sample corresponds to an integrated luminosity of 174 inverse nanobarns. The significance of the tt-bar signal against the background-only hypothesis is above five standard deviations. The measured cross section is sigma[tt-bar] = 45 +/- 8 nb, consistent with predictions from perturbative quantum chromodynamics.
Invariant mass distributions of the W candidate, $m_{jj'}$, in the 0 b category after all selections. The error bars indicate the statistical uncertainties.
Invariant mass distributions of the W candidate, $m_{jj'}$, in the 1 b category after all selections. The error bars indicate the statistical uncertainties.
Invariant mass distributions of the W candidate, $m_{jj'}$, in the $\geq$2 b category after all selections. The error bars indicate the statistical uncertainties.
The top quark pair production cross section ($\sigma_{\mathrm{t}\overline{\mathrm{t}}}$) is measured for the first time in pp collisions at a center-of-mass energy of 5.02 TeV. The data were collected by the CMS experiment at the LHC and correspond to an integrated luminosity of 27.4 pb$^{-1}$. The measurement is performed by analyzing events with at least one charged lepton. The measured cross section is $ \sigma_{\mathrm{t}\overline{\mathrm{t}}} = 69.5 \pm 6.1$ (stat) $\pm 5.6$ (syst) $\pm 1.6$ (lumi) pb, with a total relative uncertainty of 12%. The result is in agreement with the expectation from the standard model. The impact of the presented measurement on the determination of the gluon distribution function is investigated.
The measured fiducial cross sections in the $\ell$+jets and dilepton ($\rm{e}^\pm \mu^\mp$ or $\mu^\pm \mu^\mp$) decay channels. The first uncertainty is the statistical, the second is the systematic, and the last due to the integrated luminosity.
The measured total cross sections based on the $\ell$+jets (left), $\rm{e}^\pm \mu^\mp$ (middle) and $\mu^\pm \mu^\mp$ (right) decay channels. The first uncertainty is the statistical, the second is the systematic, and the last due to the integrated luminosity.
The measured total cross section in the combined $\ell$+jets and dilepton ($\rm{e}^\pm \mu^\mp$ or $\mu^\pm \mu^\mp$) decay channels. The weights of the individual measurements are 81.8% for $\ell$+jets, 13.5% for $\rm{e}^\pm \mu^\mp$, and 4.7% for $\mu^\pm \mu^\mp$ channels. The first uncertainty is the statistical, the second is the systematic, and the last due to the integrated luminosity.
The cross sections for the production of single top quarks and antiquarks in the $t$ channel, and their ratio, are measured in proton-proton collisions at a center-of-mass energy of $13~\mathrm{TeV}$. The full data set recorded in 2016 by the CMS detector at the LHC is analyzed, corresponding to an integrated luminosity of $35.9~\mathrm{fb}^{-1}$. Events with one muon or electron and two jets are selected, where one of the two jets is identified as originating from a bottom quark. A multivariate discriminator exploiting several kinematic variables is applied to separate signal from background events. The ratio $R_{t\mathrm{\text{-}ch.}}$ of the cross sections is measured to be $1.65 \pm0.02\,\text{(stat)} \pm0.04\,\text{(syst)}$. The total cross section for the production of single top quarks or antiquarks is measured to be $219.0 \pm1.5\,\text{(stat)} \pm33.0\,\text{(syst)} \,\mathrm{pb}$ and the absolute value of the CKM matrix element $V_{\mathrm{tb}}$ is determined to be $1.00 \pm0.05\,\text{(exp)} \pm0.02 \,\text{(theo)}$. All results are in agreement with the standard model predictions.
The measured cross section of top quark production in $t$-channel. The first uncertainty is the statistical, the second is due to profiled systematic sources, the third is due to the sources describing signal modelling (externalized), and the last due to the integrated luminosity (externalized).
The measured cross section of top antiquark production in $t$-channel. The first uncertainty is the statistical, the second is due to profiled systematic sources, the third is due to the sources describing signal modelling (externalized), and the last due to the integrated luminosity (externalized).
The measured inclusive cross section of production of the top quarks and antiquarks in $t$-channel. The first uncertainty is the statistical, the second is due to profiled systematic sources, the third is due to the sources describing signal modelling (externalized), and the last due to the integrated luminosity (externalized).
A measurement is presented of the associated production of a single top quark and a W boson in proton-proton collisions at $\sqrt{s}=$ 13 TeV by the CMS Collaboration at the CERN LHC. The data collected corresponds to an integrated luminosity of 35.9 fb$^{-1}$. The measurement is performed using events with one electron and one muon in the final state along with at least one jet originated from a bottom quark. A multivariate discriminant, exploiting the kinematic properties of the events, is used to separate the signal from the dominant $\mathrm{t\overline{t}}$ background. The measured cross section of 63.1 $\pm$ 1.8 (stat) $\pm$ 6.4 (syst) $\pm$ 2.1 (lumi) pb is in agreement with the standard model expectation.
The measured total cross sections based on the $\rm{e}^\pm \mu^\mp$ decay channel. The first uncertainty is the statistical, the second is the systematic, and the last due to the integrated luminosity.
Summary of the individual contributions to the uncertainty in the $\sigma_{tW}$ measurement.
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