The production of a Z boson, decaying to two charged leptons, in association with jets in proton-proton collisions at a centre-of-mass energy of 13 TeV is measured. Data recorded with the CMS detector at the LHC are used that correspond to an integrated luminosity of 2.19 fb$^{-1}$. The cross section is measured as a function of the jet multiplicity and its dependence on the transverse momentum of the Z boson, the jet kinematic variables (transverse momentum and rapidity), the scalar sum of the jet momenta, which quantifies the hadronic activity, and the balance in transverse momentum between the reconstructed jet recoil and the Z boson. The measurements are compared with predictions from four different calculations. The first two merge matrix elements with different parton multiplicities in the final state and parton showering, one of which includes one-loop corrections. The third is a fixed-order calculation with next-to-next-to-leading order accuracy for the process with a Z boson and one parton in the final state. The fourth combines the fully differential next-to-next-to-leading order calculation with next-to-next-to-leading logarithm resummation and parton showering.
Measured cross section for Z+jets as a function of the exclusive jet multiplicity, $N_{\text{jets}}$, and breakdown of the relative uncertainty.
Bin-to-bin correlation in the measured cross section for Z+jets as a function of the exclusive jet multiplicity, $N_{\text{jets}}$.
Measured cross section for Z+jets as a function of inclusive jet multiplicity, $N_{\text{jets}}^{\text{min}}$, and breakdown of the relative uncertainty.
A measurement of the differential cross sections for a W boson produced in association with jets in the muon decay channel is presented. The measurement is based on 13 TeV proton-proton collision data corresponding to an integrated luminosity of 2.2 inverse femtobarns, recorded by the CMS detector at the LHC. The cross sections are reported as functions of jet multiplicity, jet transverse momentum pT, jet rapidity, the scalar pT sum of the jets, and angular correlations between the muon and the jet for different jet multiplicities. The measured cross sections are in agreement with predictions that include multileg leading-order (LO) and next-to-LO matrix element calculations interfaced with parton showers, as well as a next-to-next-to-LO calculation for the W boson and one jet production.
The cross section measurement as a function of the exclusive jet multiplicity, for jet multiplicities of up to 6.
The cross section measurement as a function of the inclusive jet multiplicity, for jet multiplicities of up to 6.
The differential cross section measurement as a function of the transverse momentum of the first leading jet.
Differential cross sections for a W boson produced in association with jets are measured in a data sample of proton-proton collisions at a center-of-mass energy of 8 TeV recorded with the CMS detector and corresponding to an integrated luminosity of 19.6 inverse femtobarns. The W bosons are identified through their decay mode W to mu nu. The cross sections are reported as functions of jet multiplicity, transverse momenta, and the scalar sum of jet transverse momenta (HT) for different jet multiplicities. Distributions of the angular correlations between the jets and the muon are examined, as well as the average number of jets as a function of HT and as a function of angular variables. The measured differential cross sections are compared with tree-level and higher-order recent event generators, as well as next-to-leading-order and next-to-next-to-leading-order theoretical predictions. The agreement of the generators with the measurements builds confidence in their use for the simulation of W+jets background processes in searches for new physics at the LHC.
The cross section measurement as a function of the exclusive jet multiplicity, for jet multiplicities of up to 7.
The cross section measurement as a function of the exclusive jet multiplicity, for jet multiplicities of up to 7.
The cross section measurement as a function of the inclusive jet multiplicity, for jet multiplicities of up to 7.
The cross section for pair production of top quarks (t-tbar) with high transverse momenta is measured in pp collisions, collected with the CMS detector at the LHC with sqrt(s) = 8 TeV in data corresponding to an integrated luminosity of 19.7 inverse femtobarns. The measurement is performed using lepton+jets events, where one top quark decays semileptonically, while the second top quark decays to a hadronic final state. The hadronic decay is reconstructed as a single, large-radius jet, and identified as a top quark candidate using jet substructure techniques. The integrated cross section and the differential cross sections as a function of top quark pt and rapidity are measured at particle level within a fiducial region related to the detector-level requirements and at parton level. The particle-level integrated cross section is found to be sigma[t-tbar] = 0.499 +/- 0.035 (stat+syst) +/- 0.095 (theory) +/- 0.013 (lumi) pb for top quark pt > 400 GeV. The parton-level measurement is sigma[t-tbar] = 1.44 +/- 0.10 (stat+syst) +/- 0.29 (theory) +/- 0.04 (lumi) pb. The integrated and differential cross section results are compared to predictions from several event generators.
The measurements of the integrated cross sections for $p_T^t > 400$ GeV.
Differential $t\bar{t}$ cross section in bins of $p_T$ for the $t$ jet at the particle level and the top quark at parton level.
Differential $t\bar{t}$ cross section in bins of $y$ for the $t$ jet at the particle level and the top quark at parton level.
The production of Z bosons in pPb collisions at sqrt(s[NN]) = 5.02 TeV is studied by the CMS experiment via the electron and muon decay channels. The inclusive cross section is compared to pp collision predictions, and found to scale with the number of elementary nucleon-nucleon collisions. The differential cross sections as a function of the Z boson rapidity and transverse momentum are measured. Though they are found to be consistent within uncertainty with theoretical predictions both with and without nuclear effects, the forward-backward asymmetry suggests the presence of nuclear effects at large rapidities. These results provide new data for constraining nuclear parton distribution functions.
Differential cross section of the Z bosons in pPb collisions as a function of rapidity in the fiducial region for the combined leptonic decay channel.
Forward-backward asymmetry (AFB) distribution of the Z bosons in pPb collisions as a function of rapidity in the fiducial region for the combined leptonic decay channel.
Differential cross section of the Z bosons in pPb collisions as a function of transverse momentum in the fiducial region for the combined leptonic decay channel.
The production cross sections of the B+, B0, and B0s mesons, and of their charge conjugates, are measured via exclusive hadronic decays in pPb collisions at the center-of-mass energy sqrt(s_NN) = 5.02 TeV with the CMS detector at the CERN LHC. The data set used for this analysis corresponds to an integrated luminosity of 34.6 inverse nanobarns. The production cross sections are measured in the transverse momentum range between 10 and 60 GeV/c. No significant modification is observed compared to proton-proton perturbative QCD calculations scaled by the number of incoherent nucleon-nucleon collisions. These results provide a baseline for the study of in-medium b quark energy loss in PbPb collisions.
The measured $p_{\rm{T}}$-differential production cross section of $B^{+}$ in $p$ + Pb collisions at $\sqrt{s_{NN}} = 5.02$ TeV, together with the cross section calculated by the FONLL model.
The measured $p_{\rm{T}}$-differential production cross section of $B^{0}$ in $p$ + Pb collisions at $\sqrt{s_{NN}} = 5.02$ TeV, together with the cross section calculated by the FONLL model.
The measured $p_{\rm{T}}$-differential production cross section of $B_{s}^{0}$ in $p$ + Pb collisions at $\sqrt{s_{NN}} = 5.02$ TeV, together with the cross section calculated by the FONLL model.
Measurements of the differential and double-differential Drell-Yan cross sections are presented using an integrated luminosity of 4.5(4.8) inverse femtobarns in the dimuon (dielectron) channel of proton-proton collision data recorded with the CMS detector at the LHC at $\sqrt{s}$ = 7 TeV. The measured inclusive cross section in the Z-peak region (60-120 GeV) is $\sigma(\ell \ell)$ = 986.4 +/- 0.6 (stat.) +/- 5.9 (exp. syst.) +/- 21.7 (th. syst.) +/- 21.7 (lum.) pb for the combination of the dimuon and dielectron channels. Differential cross sections $d\sigma/dm$ for the dimuon, dielectron, and combined channels are measured in the mass range 15 to 1500 GeV and corrected to the full phase space. Results are also presented for the measurement of the double-differential cross section $d^2\sigma/dm d |y|$ in the dimuon channel over the mass range 20 to 1500 GeV and absolute dimuon rapidity from 0 to 2.4. These measurements are compared to the predictions of perturbative QCD calculations at next-to-leading and next-to-next-to-leading orders using various sets of parton distribution functions.
Normalization factors for the cross section measurements from the Z-peak region (60 < M < 120 GeV) with associated uncertainties. The measurements are given in the muon, electron and combined channels. The three systematic uncertainties correspond to experimental, theoretical and luminosity.
The DY cross section measurements for the muon channel normalized to the Z-peak region, pre- and post-FSR, as measured in the full acceptance and for the CMS detector acceptance. The uncertainty indicates the experimental (statistical and systematic) uncertainties summed in quadrature with the theoretical uncertainty resulting from the model-dependent kinematic distributions inside each bin.
The DY cross section measurements for the electron channel normalized to the Z-peak region, pre- and post-FSR, as measured in the full acceptance and for the CMS detector acceptance. The uncertainty indicates the experimental (statistical and systematic) uncertainties summed in quadrature with the theoretical uncertainty resulting from the model-dependent kinematic distributions inside each bin.
Rapidity distributions are presented for events containing either a Z boson or a photon with a single jet in proton-proton collisions produced at the CERN LHC. The data, collected with the CMS detector at $\sqrt{s}$ = 7 TeV, correspond to an integrated luminosity of 5.0 inverse femtobarns. The individual rapidity distributions of the boson and the jet are consistent within 5% with expectations from perturbative QCD. However, QCD predictions for the sum and the difference in rapidities of the two final-state objects show discrepancies with CMS data. In particular, next-to-leading-order QCD calculations, and two common Monte Carlo event generators using different methods to match matrix-element partons with parton showers, appear inconsistent with the data as well as with each other.
Distributions of |YZ| normalized to unity. The data are shown after correcting for efficiency and resolution, and displayed with statistical and systematic uncertainties combined in quadrature.
Distributions of |YJet| normalized to unity. The data are shown after correcting for efficiency and resolution, and displayed with statistical and systematic uncertainties combined in quadrature.
Distributions of 0.5*|YZ+YJet| normalized to unity. The data are shown after correcting for efficiency and resolution, and displayed with statistical and systematic uncertainties combined in quadrature.
The Lambda(b) differential production cross section and the cross section ratio anti-Lambda(b)/Lambda(b) are measured as functions of transverse momentum pt(Lambda(b)) and rapidity abs(y(Lambda(b))) in pp collisions at sqrt(s) = 7 TeV using data collected by the CMS experiment at the LHC. The measurements are based on Lambda(b) decays reconstructed in the exclusive final state J/Psi Lambda, with the subsequent decays J/Psi to an opposite-sign muon pair and Lambda to proton pion, using a data sample corresponding to an integrated luminosity of 1.9 inverse femtobarns. The product of the cross section times the branching ratio for Lambda(b) to J/Psi Lambda versus pt(Lambda(b)) falls faster than that of b mesons. The measured value of the cross section times the branching ratio for pt(Lambda(b)) > 10 GeV and abs(y(Lambda(b))) < 2.0 is 1.06 +/- 0.06 +/- 0.12 nb, and the integrated cross section ratio for anti-Lambda(b)/Lambda(b) is 1.02 +/- 0.07 +/- 0.09, where the uncertainties are statistical and systematic, respectively.
The measured Lambda/B integrated cross section and the ratio of anti-Lambda/B to Lambda/B cross sections.
The measured Lambda/B differential cross section and the ratio of anti-Lambda/B to Lambda/B cross sections as a function of the Lambda/B transverse momentum The second and third systematic errors on the cross sections are the common luminosity and branching fraction uncertainties respectively.
The measured Lambda/B differential cross section and the ratio of anti-Lambda/B to Lambda/B cross sections as a function of the Lambda/B absolute rapidity. The second and third systematic errors on the cross sections are the common luminosity and branching fraction uncertainties respectively.
A study of dijet production in proton-proton collisions was performed at sqrt(s) = 7 TeV for jets with pt > 35 GeV and abs(y) < 4.7 using data collected with the CMS detector at the LHC in 2010. Events with at least one pair of jets are denoted as 'inclusive'. Events with exactly one pair of jets are called 'exclusive'. The ratio of the cross section of all pairwise combinations of jets to the exclusive dijet cross section as a function of the rapidity difference between jets abs(Delta(y)) is measured for the first time up to abs(Delta(y)) = 9.2. The ratio of the cross section for the pair consisting of the most forward and the most backward jet from the inclusive sample to the exclusive dijet cross section is also presented. The predictions of the Monte Carlo event generators PYTHIA6 and PYTHIA8 agree with the measurements. In both ratios the HERWIG++ generator exhibits a more pronounced rise versus abs(Delta(y)) than observed in the data. The BFKL-motivated generators CASCADE and HEJ+ARIADNE predict for these ratios a significantly stronger rise than observed.
Inclusive to exclusive dijet production ratio.
Mueller-Navelet to exclusive dijet production ratio.
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