Measurements of fiducial and total inclusive cross sections for W and Z boson production are presented in proton-proton collisions at $\sqrt{s}$ = 5.02 and 13 TeV. Electron and muon decay modes ($ell$ = e or$\mu$) are studied in the data collected with the CMS detector in 2017, in dedicated runs with reduced instantaneous luminosity. The data sets correspond to integrated luminosities of 298 $\pm$ 6 pb$^{-1}$ at 5.02 TeV and 206 $\pm$ 5 pb$^{-1}$ at 13 TeV. Measured values of the products of the total inclusive cross sections and the branching fractions at 5.02 TeV are $\sigma$(pp $\to$ W+X)$\mathcal{B}$(W $\to$$\ell\nu$) = 7300 $\pm$ 10 (stat) $\pm$ 60 (syst) $\pm$ 140 (lumi) pb, and $\sigma$(pp $\to$ Z+X)$\mathcal{B}$(Z $\to$$\ell^+\ell^-$) = 669 $\pm$ 2 (stat) $\pm$ 6 (syst) $\pm$ 13 (lumi) pb for the dilepton invariant mass in the range of 60-120 GeV. The corresponding results at 13 TeV are 20480 $\pm$ 10 (stat) $\pm$ 170 (syst) $\pm$ 470 (lumi) pb and 1952 $\pm$ 4 (stat) $\pm$ 18 (syst) $\pm$ 45 (lumi) pb. The measured values agree with cross section calculations at next-to-next-to-leading-order in perturbative quantum chromodynamics. Fiducial and total inclusive cross sections, ratios of cross sections of W$^+$ and W$^-$ production as well as inclusive W and Z boson production, and ratios of these measurements at 5.02 and 13 TeV are reported.
Distributions of $m_T$ in the $W^{+}$ signal selection for e final states for the pp collisions at $\sqrt{s}=$ 5TeV after the maximum likelihood fit. The EW backgrounds include the contributions from DY, $W\to\tau\nu$, and diboson processes.
Distributions of $m_T$ in the $W^{+}$ signal selection for mu final states for the pp collisions at $\sqrt{s}=$ 5TeV after the maximum likelihood fit. The EW backgrounds include the contributions from DY, $W\to\tau\nu$, and diboson processes.
Distributions of $m_T$ in the $W^{+}$ signal selection for e final states for the pp collisions at $\sqrt{s}=$ 13TeV after the maximum likelihood fit. The EW backgrounds include the contributions from DY, $W\to\tau\nu$, and diboson processes.
The Large Hadron Collider at CERN, delivering proton-proton collisions at much higher energies and far higher luminosities than previous machines, has enabled a comprehensive programme of measurements of the standard model (SM) processes by the CMS experiment. These unprecedented capabilities facilitate precise measurements of the properties of a wide array of processes, the most fundamental being cross sections. The discovery of the Higgs boson and the measurement of its mass became the keystone of the SM. Knowledge of the mass of the Higgs boson allows precision comparisons of the predictions of the SM with the corresponding measurements. These measurements span the range from one of the most copious SM processes, the total inelastic cross section for proton-proton interactions, to the rarest ones, such as Higgs boson pair production. They cover the production of Higgs bosons, top quarks, single and multibosons, and hadronic jets. Associated parameters, such as coupling constants, are also measured. These cross section measurements can be pictured as a descending stairway, on which the lowest steps represent the rarest processes allowed by the SM, some never seen before.
Cross sections of selected high-energy processes measured by the CMS experiment. Measurements performed at different LHC pp collision energies are marked by unique symbols and the coloured bands indicate the combined statistical and systematic uncertainty of the measurement. Grey bands indicate the uncertainty of the corresponding SM theory predictions. Shaded hashed bars indicate the excluded cross section region for a production process with the measured 95% CL upper limit on the process indicated by the solid line of the same colour.
Summary of production cross section measurements involving top quarks. Measurements performed at different LHC pp collision energies are marked by unique symbols and the coloured bands indicate the combined statistical and systematic uncertainty of the measurement. Grey bands indicate the uncertainty of the corresponding SM theory predictions. Shaded hashed bars indicate the excluded cross section region for a production process with the measured 95% C.L. upper limit on the process indicated by the solid line of the same colour.
Summary of measurements of jet cross sections and electroweak processes in association with jets. Measurements performed at different LHC pp collision energies are marked by unique symbols and the coloured bands indicate the combined statistical and systematic uncertainty of the measurement. Grey bands indicate the uncertainty of the corresponding SM theory predictions. Shaded hashed bars indicate the excluded cross section region for a production process with the measured 95% C.L. upper limit on the process indicated by the solid line of the same colour. Versions of these plots in pdf format with links to the publications can be found at https://cms-results.web.cern.ch/cms-results/public-results/publications/SMP-23-004/.
A combination of fifteen top quark mass measurements performed by the ATLAS and CMS experiments at the LHC is presented. The data sets used correspond to an integrated luminosity of up to 5 and 20$^{-1}$ of proton-proton collisions at center-of-mass energies of 7 and 8 TeV, respectively. The combination includes measurements in top quark pair events that exploit both the semileptonic and hadronic decays of the top quark, and a measurement using events enriched in single top quark production via the electroweak $t$-channel. The combination accounts for the correlations between measurements and achieves an improvement in the total uncertainty of 31% relative to the most precise input measurement. The result is $m_\mathrm{t}$ = 172.52 $\pm$ 0.14 (stat) $\pm$ 0.30 (syst) GeV, with a total uncertainty of 0.33 GeV.
Uncertainties on the $m_{t}$ values extracted in the LHC, ATLAS, and CMS combinations arising from the categories described in the text, sorted in order of decreasing value of the combined LHC uncertainty.
Despite the f$_0$(980) hadron having been discovered half a century ago, the question about its quark content has not been settled: it might be an ordinary quark-antiquark ($\mathrm{q\bar{q}}$) meson, a tetraquark ($\mathrm{q\bar{q}q\bar{q}}$) exotic state, a kaon-antikaon ($\mathrm{K\bar{K}}$) molecule, or a quark-antiquark-gluon ($\mathrm{q\bar{q}g}$) hybrid. This paper reports strong evidence that the f$_0$(980) state is an ordinary $\mathrm{q\bar{q}}$ meson, inferred from the scaling of elliptic anisotropies ($v_2$) with the number of constituent quarks ($n_\mathrm{q}$), as empirically established using conventional hadrons in relativistic heavy ion collisions. The f$_0$(980) state is reconstructed via its dominant decay channel f$_0$(980) $\to$$\pi^+\pi^-$, in proton-lead collisions recorded by the CMS experiment at the LHC, and its $v_2$ is measured as a function of transverse momentum ($p_\mathrm{T}$). It is found that the $n_q$ = 2 ($\mathrm{q\bar{q}}$ state) hypothesis is favored over $n_q$ = 4 ($\mathrm{q\bar{q}q\bar{q}}$ or $\mathrm{K\bar{K}}$ states) by 7.7, 6.3, or 3.1 standard deviations in the $p_\mathrm{T}$$\lt$ 10, 8, or 6 GeV/$c$ ranges, respectively, and over $n_\mathrm{q}$ = 3 ($\mathrm{q\bar{q}g}$ hybrid state) by 3.5 standard deviations in the $p_\mathrm{T}$$\lt$ 8 GeV/$c$ range. This result represents the first determination of the quark content of the f$_0$(980) state, made possible by using a novel approach, and paves the way for similar studies of other exotic hadron candidates.
The elliptic flow, $v_{2}$, for $f_0(980)$ as a function of $p_{T}$ in pPb collision at 8.16 TeV.
The elliptic flow after nonflow subtraction, $v_{2}^{sub}$, for $f_0(980)$ as a function of $p_{T}$ in pPb collision at 8.16 TeV.
The elliptic flow after nonflow subtraction, $v_{2}^{sub}/2$, for $f_0(980)$ as a function of $<KE_{T}>/2$ in pPb collision at 8.16 TeV.
The azimuthal anisotropy of $\Upsilon$(1S) mesons in high-multiplicity proton-lead collisions is studied using data collected by the CMS experiment at a nucleon-nucleon center-of-mass energy of 8.16 TeV. The $\Upsilon$(1S) mesons are reconstructed using their dimuon decay channel. The anisotropy is characterized by the second Fourier harmonic coefficients, found using a two-particle correlation technique, in which the $\Upsilon$(1S) mesons are correlated with charged hadrons. A large pseudorapidity gap is used to suppress short-range correlations. Nonflow contamination from the dijet background is removed using a low-multiplicity subtraction method, and the results are presented as a function of $\Upsilon$(1S) transverse momentum. The azimuthal anisotropies are smaller than those found for charmonia in proton-lead collisions at the same collision energy, but are consistent with values found for $\Upsilon$(1S) mesons in lead-lead interactions at a nucleon-nucleon center-of-mass energy of 5.02 TeV.
The $p_{\mathrm{T}}$ dependent $v_{2}^{\textrm{sub}}$ values of $\Upsilon(1S)$ mesons measured in the high-multiplicity region of $70 \leq N^{\text{offline}}_{\text{trk}} < 300$, where a low-multiplicity region of $N^{\text{offline}}_{\text{trk}} < 50$ is used to estimate and correct for the dijet contribution.
The $p_{\mathrm{T}}$ dependent $v_{2}^{\textrm{sub}}$ values of $\Upsilon(1S)$ mesons measured in the high-multiplicity region of $70 \leq N^{\text{offline}}_{\text{trk}} < 300$, where a low-multiplicity region of $N^{\text{offline}}_{\text{trk}} < 50$ is used to estimate and correct for the dijet contribution.
Measurements of the charge-dependent two-particle angular correlation function in proton-lead (pPb) collisions at a nucleon-nucleon center-of-mass energy of $\sqrt{s_\mathrm{NN}}$ = 8.16 TeV and lead-lead (PbPb) collisions at $\sqrt{s_\mathrm{NN}}$ = 5.02 TeV are reported. The pPb and PbPb data sets correspond to integrated luminosities of 186 nb$^{-1}$ and 0.607 nb$^{-1}$, respectively, and were collected using the CMS detector at the CERN LHC. The charge-dependent correlations are characterized by balance functions of same- and opposite-sign particle pairs. The balance functions, which contain information about the creation time of charged particle pairs and the development of collectivity, are studied as functions of relative pseudorapidity ($\Delta \eta$) and relative azimuthal angle ($\Delta \phi$), for various multiplicity and transverse momentum ($p_\mathrm{T}$) intervals. A multiplicity dependence of the balance function is observed in $\Delta \eta$ and $\Delta \phi$ for both systems. The width of the balance functions decreases toward high-multiplicity collisions in the momentum region $\lt$ 2 GeV, for pPb and PbPb results. Integrals of the balance functions are presented in both systems, and a mild dependence of the charge-balancing fractions on multiplicity is observed. No multiplicity dependence is observed at higher transverse momentum. The data are compared with HYDJET, HIJING and AMPT generator predictions, none of which capture completely the multiplicity dependence seen in the data. The comparison of results with different center-of-mass energies suggest that the balance functions become narrower at higher energies, which is consistent with the idea of delayed hadronization and the effect of radial flow.
$\Delta\eta$ projection of balance function in low $p_{T}$ in 0-10% centrality
$\Delta\eta$ projection of balance function in low $p_{T}$ in 30-40% centrality
$\Delta\eta$ projection of balance function in low $p_{T}$ in 70-80% centrality
A combination of measurements of the inclusive top-quark pair production cross-section performed by ATLAS and CMS in proton-proton collisions at centre-of-mass energies of 7 and 8 TeV at the LHC is presented. The cross-sections are obtained using top-quark pair decays with an opposite-charge electron-muon pair in the final state and with data corresponding to an integrated luminosity of about 5 fb$^{-1}$ at $\sqrt{s}=7$ TeV and about 20 fb$^{-1}$ at $\sqrt{s}=8$ TeV for each experiment. The combined cross-sections are determined to be $178.5 \pm 4.7$ pb at $\sqrt{s}=7$ TeV and $243.3^{+6.0}_{-5.9}$ pb at $\sqrt{s}=8$ TeV with a correlation of 0.41, using a reference top-quark mass value of 172.5 GeV. The ratio of the combined cross-sections is determined to be $R_{8/7}= 1.363\pm 0.032$. The combined measured cross-sections and their ratio agree well with theory calculations using several parton distribution function (PDF) sets. The values of the top-quark pole mass (with the strong coupling fixed at 0.118) and the strong coupling (with the top-quark pole mass fixed at 172.5 GeV) are extracted from the combined results by fitting a next-to-next-to-leading-order plus next-to-next-to-leading-log QCD prediction to the measurements. Using a version of the NNPDF3.1 PDF set containing no top-quark measurements, the results obtained are $m_t^\text{pole} = 173.4^{+1.8}_{-2.0}$ GeV and $\alpha_\text{s}(m_Z)= 0.1170^{+ 0.0021}_{-0.0018}$.
Full covariance matrix including all systematic uncertainties expressed as nuisance parameters. With the exception of the cross section parameters, all parameters were normalised to 1 before the fit. Therefore, the diagonal elements represent the constraint in quadrature.
Full covariance matrix including all systematic uncertainties expressed as nuisance parameters. With the exception of the cross section parameters, all parameters were normalised to 1 before the fit. Therefore, the diagonal elements represent the constraint in quadrature.
The production of prompt $D^0$ mesons in proton-lead collisions in the forward and backward configurations at a center-of-mass energy per nucleon pair of $\sqrt{s_\mathrm{NN}} = 8.16~\mathrm{TeV}$ is measured by the LHCb experiment. The nuclear modification factor of prompt $D^0$ mesons is determined as a function of the transverse momentum $p_\mathrm{T}$, and rapidity in the nucleon-nucleon center-of-mass frame $y^*$. In the forward rapidity region, significantly suppressed production with respect to $pp$ collisions is measured, which provides significant constraints of nuclear parton distributions and hadron production down to the very low Bjorken-$x$ region of $\sim 10^{-5}$. In the backward rapidity region, a suppression with a significance of 2.0 - 3.8 standard deviations compared to nPDF expectations is found in the kinematic region of $p_\mathrm{T}>6~\mathrm{GeV}/c$ and $-3.25<y^*<-2.5$, corresponding to $x\sim 0.01$.
Double-differential cross-sections for prompt $D^0$ mesons in intervals of $p_\mathrm{T}$ and $y^\ast$ in forward rapidity regions.
Double-differential cross-sections for prompt $D^0$ mesons in intervals of $p_\mathrm{T}$ and $y^\ast$ in forward rapidity regions.
Double-differential cross-sections for prompt $D^0$ mesons in intervals of $p_\mathrm{T}$ and $y^\ast$ in backward rapidity regions.
The production cross-sections of $J/\psi$ mesons in proton-proton collisions at a centre-of-mass energy of $\sqrt{s}=5$ TeV are measured using a data sample corresponding to an integrated luminosity of $9.13\pm0.18~\text{pb}^{-1}$, collected by the LHCb experiment. The cross-sections are measured differentially as a function of transverse momentum, $p_{\text{T}}$, and rapidity, $y$, and separately for $J/\psi$ mesons produced promptly and from beauty hadron decays (nonprompt). With the assumption of unpolarised $J/\psi$ mesons, the production cross-sections integrated over the kinematic range $0<p_{\text{T}}<20~\text{GeV}/c$ and $2.0<y<4.5$ are $8.154\pm0.010\pm0.283~\mu\text{b}$ for prompt $J/\psi$ mesons and $0.820\pm0.003\pm0.034~\mu\text{b}$ for nonprompt $J/\psi$ mesons, where the first uncertainties are statistical and the second systematic. These cross-sections are compared with those at $\sqrt{s}=8$ TeV and $13$ TeV, and are used to update the measurement of the nuclear modification factor in proton-lead collisions for $J/\psi$ mesons at a centre-of-mass energy per nucleon pair of $\sqrt{s_{\text{NN}}}=5$ TeV. The results are compared with theoretical predictions.
Double-differential production cross-sections for prompt $J/\psi$ mesons in ($p_\text{T},y$) intervals. The first uncertainties are statistical, the second are correlated systematic uncertainties shared between intervals, the third are uncorrelated systematic uncertainties, and the last are correlated between $p_\text{T}$ intervals and uncorrelated between $y$ intervals.
Double-differential production cross-sections for nonprompt $J/\psi$ mesons in ($p_\text{T},y$) intervals. The first uncertainties are statistical, the second are correlated systematic uncertainties shared between intervals, the third are uncorrelated systematic uncertainties, and the last are correlated between $p_\text{T}$ intervals and uncorrelated between $y$ intervals.
Single-differential production cross-sections for prompt $J/\psi$ mesons as a function of $p_\text{T}$. The first uncertainties are statistical, the second are correlated systematic uncertainties shared between intervals, and the last are uncorrelated systematic uncertainties.
The production of J/$\psi$ mesons is studied in proton-lead collisions at the centre-of-mass energy per nucleon pair $\sqrt{s_{\text{NN}}}=8.16$ TeV with the LHCb detector at the LHC. The double differential cross-sections of prompt and nonprompt J/$\psi$ production are measured as functions of the J/$\psi$ transverse momentum and rapidity in the nucleon-nucleon centre-of-mass frame. Forward-to-backward ratios and nuclear modification factors are determined. The results are compared with theoretical calculations based on collinear factorisation using nuclear parton distribution functions, on the colour glass condensate or on coherent energy loss models.
The total integrated cross sections for prompt $J/\psi$ production, assuming no polarisation, and $J/\psi$ production from $b$-hadron decays in the rapidity range $1.5 < y^* < 4.0$ in the nucleon-nucleon centre-of-mass frame measured in the proton-lead beam configuration and transverse momentum 0-14 GeV/c. The first quoted uncertainty indicates the bin-by-bin correlated systematic uncertainty and the second is the bin-by-bin uncorrelated systematic uncertainty.
The total integrated cross sections for prompt $J/\psi$ production, assuming no polarisation, and $J/\psi$ production from $b$-hadron decays in the rapidity range $-5.0 < y^* < -2.5$ in the nucleon-nucleon centre-of-mass frame measured in the lead-proton beam configuration and transverse momentum 0-14 GeV/c. The first quoted uncertainty indicates the bin-by-bin correlated systematic uncertainty and the second is the bin-by-bin uncorrelated systematic uncertainty
The double-differential cross sections for prompt $J/\psi$ production, assuming no polarisation, as a function of transverse momentum for the rapidity range $1.5 < y^* < 4.0$ in the nucleon-nucleon centre-of-mass frame. The first quoted uncertainty indicates the bin-by-bin correlated systematic uncertainty and the second is the bin-by-bin uncorrelated systematic uncertainty.
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