Measurement of associated Z + charm production in proton-proton collisions at $\sqrt{s} = $ 8 TeV

The CMS collaboration Sirunyan, A.M. ; Tumasyan, Armen ; Adam, Wolfgang ; et al.
Eur.Phys.J.C 78 (2018) 287, 2018.
Inspire Record 1634835 DOI 10.17182/hepdata.85868

A study of the associated production of a Z boson and a charm quark jet (Z + c), and a comparison to production with a b quark jet (Z + b), in pp collisions at a centre-of-mass energy of 8 TeV are presented. The analysis uses a data sample corresponding to an integrated luminosity of 19.7 fb$^{-1}$, collected with the CMS detector at the CERN LHC. The Z boson candidates are identified through their decays into pairs of electrons or muons. Jets originating from heavy flavour quarks are identified using semileptonic decays of c or b flavoured hadrons and hadronic decays of charm hadrons. The measurements are performed in the kinematic region with two leptons with $p_{\rm T}^{\ell} > $ 20 GeV, ${|\eta^{\ell}|} < $ 2.1, 71 $ < m_{\ell\ell} < $ 111 GeV, and heavy flavour jets with $p_{\rm T}^{{\rm jet}} > $ 25 GeV and ${|\eta^{{\rm jet}}|} < $ 2.5. The Z + c production cross section is measured to be $\sigma({\mathrm{p}}{\mathrm{p}} \rightarrow \mathrm{Z} + \mathrm{c} + \mathrm{X}) {\cal B}(\mathrm{Z} \rightarrow \ell^+\ell^-) = $ 8.8 $ \pm $ 0.5 (stat) $ \pm $ 0.6 (syst) pb. The ratio of the Z + c and Z + b production cross sections is measured to be $\sigma({\mathrm{p}}{\mathrm{p}} \rightarrow \mathrm{Z} + \mathrm{c} + \mathrm{X}) / \sigma({\mathrm{p}}{\mathrm{p}} \rightarrow \mathrm{Z} + \mathrm{b} + \mathrm{X}) = $ 2.0 $ \pm $ 0.2 (stat) $ \pm $ 0.2 (syst). The Z + c production cross section and the cross section ratio are also measured as a function of the transverse momentum of the Z boson and of the heavy flavour jet. The measurements are compared with theoretical predictions.

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Measurement of four-jet production in proton-proton collisions at sqrt(s)=7 TeV

The CMS collaboration Chatrchyan, Serguei ; Khachatryan, Vardan ; Sirunyan, Albert M ; et al.
Phys.Rev.D 89 (2014) 092010, 2014.
Inspire Record 1273574 DOI 10.17182/hepdata.66510

Measurements of the differential cross sections for the production of exactly four jets in proton-proton collisions are presented as a function of the transverse momentum pt and pseudorapidity eta, together with the correlations in azimuthal angle and the pt balance among the jets. The data sample was collected in 2010 at a center-of-mass energy of 7 TeV with the CMS detector at the LHC, with an integrated luminosity of 36 inverse picobarns. The cross section for a final state with a pair of hard jets with pt > 50 GeV and another pair with pt > 20 GeV within abs(eta) < 4.7 is measured to be sigma = 330 +- 5 (stat.) +- 45 (syst.) nb. It is found that fixed-order matrix element calculations including parton showers describe the measured differential cross sections in some regions of phase space only, and that adding contributions from double parton scattering brings the Monte Carlo predictions closer to the data.

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Measurements of jet multiplicity and differential production cross sections of Z+jets events in proton-proton collisions at sqrt(s)=7 TeV

The CMS collaboration Khachatryan, Vardan ; Sirunyan, Albert M ; Tumasyan, Armen ; et al.
Phys.Rev.D 91 (2015) 052008, 2015.
Inspire Record 1310737 DOI 10.17182/hepdata.67635

Measurements of differential cross sections are presented for the production of a Z boson and at least one hadronic jet in proton-proton collisions at sqrt(s) = 7 TeV, recorded by the CMS detector, using a data sample corresponding to an integrated luminosity of 4.9 inverse femtobarns. The jet multiplicity distribution is measured for up to six jets. The differential cross sections are measured as a function of jet transverse momentum and pseudorapidity for the four highest transverse momentum jets. The distribution of the scalar sum of jet transverse momenta is also measured as a function of the jet multiplicity. The measurements are compared with theoretical predictions at leading and next-to-leading order in perturbative QCD.

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Differential cross section measurements for the production of a W boson in association with jets in proton-proton collisions at sqrt(s) = 7 TeV

The CMS collaboration Khachatryan, Vardan ; Sirunyan, Albert M ; Tumasyan, Armen ; et al.
Phys.Lett.B 741 (2015) 12-37, 2015.
Inspire Record 1303894 DOI 10.17182/hepdata.67318

Measurements are reported of differential cross sections for the production of a W boson, which decays into a muon and a neutrino, in association with jets, as a function of several variables, including the transverse momenta (pt) and pseudorapidities of the four leading jets, the scalar sum of jet transverse momenta (HT), and the difference in azimuthal angle between the directions of each jet and the muon. The data sample of pp collisions at a centre-of-mass energy of 7 TeV was collected with the CMS detector at the LHC and corresponds to an integrated luminosity of 5.0 inverse femtobarns. The measured cross sections are compared to predictions from Monte Carlo generators, MADGRAPH + PYTHIA and SHERPA, and to next-to-leading-order calculations from BLACKHAT + SHERPA. The differential cross sections are found to be in agreement with the predictions, apart from the pt distributions of the leading jets at high pt values, the distributions of the HT at high-HT and low jet multiplicity, and the distribution of the difference in azimuthal angle between the leading jet and the muon at low values.

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Measurement of the pp to ZZ production cross section and constraints on anomalous triple gauge couplings in four-lepton final states at sqrt(s) = 8 TeV

The CMS collaboration Khachatryan, Vardan ; Sirunyan, Albert M ; Tumasyan, Armen ; et al.
Phys.Lett.B 740 (2015) 250-272, 2015.
Inspire Record 1298807 DOI 10.17182/hepdata.67317

A measurement of inclusive ZZ production cross section and constraints on anomalous triple gauge couplings in proton-proton collisions at sqrt(s) = 8 TeV are presented. A data sample, corresponding to an integrated luminosity of 19.6 inverse femtobarns was collected with the CMS experiment at the LHC. The measurements are performed in the leptonic decay modes ZZ to lll'l', where l = e, mu and l' = e, mu, tau. The measured total cross section, sigma(pp to ZZ) = 7.7 +/- 0.5 (stat.) +0.5-0.4 (syst.) +/- 0.4 (theo.) +/- 0.2 (lum.) pb for both Z bosons produced in the mass range 60 < m[Z] < 120 GeV, is consistent with standard model predictions. Differential cross sections are measured and well described by the theoretical predictions. The invariant mass distribution of the four-lepton system is used to set limits on anomalous ZZZ and ZZ gamma couplings at the 95% confidence level: -0.004 < f[4,Z] < 0.004, -0.004 < f[5,Z] < 0.004, -0.005 < f[4,gamma] < 0.005, and -0.005 < f[5,gamma] < 0.005.

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Measurement of the inelastic proton-proton cross section at sqrt(s) = 7 TeV

The CMS collaboration Chatrchyan, Serguei ; Khachatryan, Vardan ; Sirunyan, Albert M ; et al.
Phys.Lett.B 722 (2013) 5-27, 2013.
Inspire Record 1193338 DOI 10.17182/hepdata.68126

A measurement is presented of the inelastic proton-proton cross section at a centre-of-mass energy of sqrt(s) = 7 TeV. Using the CMS detector at the LHC, the inelastic cross section is measured through two independent methods based on information from (i) forward calorimetry (for pseudorapidity 3 < abs(eta) < 5), in collisions where at least one proton loses more than 5E-6 of its longitudinal momentum, and (ii) the central tracker (abs(eta) < 2.4), in collisions containing an interaction vertex with more than 1, 2, or 3 tracks with transverse momenta pT > 200 MeV. The measurements cover a large fraction of the inelastic cross section for particle production over about 9 units of pseudorapidity and down to small transverse momenta. The results are compared with those of other experiments, and with models used to describe high-energy hadronic interactions.

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Studies of inclusive four-jet production with two b-tagged jets in proton-proton collisions at 7 TeV

The CMS collaboration Khachatryan, Vardan ; Sirunyan, Albert M ; Tumasyan, Armen ; et al.
Phys.Rev.D 94 (2016) 112005, 2016.
Inspire Record 1486238 DOI 10.17182/hepdata.75375

Measurements are presented of the cross section for the production of at least four jets, of which at least two originate from b quarks, in proton-proton collisions. Data collected with the CMS detector at the LHC at a center-of-mass energy of 7 TeV are used, corresponding to an integrated luminosity of 3 inverse picobarns. The cross section is measured as a function of the jet transverse momentum for pt > 20 GeV, and of the jet pseudorapidity for abs(eta) < 2.4 (b jets), 4.7 (untagged jets). The correlations in azimuthal angle and pt between the jets are also studied. The inclusive cross section is measured to be sigma(pp to 2 b + 2 j + X) = 69 +/- 3 (stat) +/- 24 (syst) nb. The eta and pt distributions of the four jets and the correlations between them are well reproduced by event generators that combine perturbative QCD calculations at next-to-leading-order accuracy with contributions from parton showers and multiparton interactions.

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Inclusive b-jet production in pp collisions at sqrt(s)=7 TeV

The CMS collaboration Chatrchyan, Serguei ; Khachatryan, Vardan ; Sirunyan, Albert M ; et al.
JHEP 04 (2012) 084, 2012.
Inspire Record 1089835 DOI 10.17182/hepdata.58503

The inclusive b-jet production cross section in pp collisions at a center-of-mass energy of 7 TeV is measured using data collected by the CMS experiment at the LHC. The cross section is presented as a function of the jet transverse momentum in the range 18 < pT < 200 GeV for several rapidity intervals. The results are also given as the ratio of the b-jet production cross section to the inclusive jet production cross section. The measurement is performed with two different analyses, which differ in their trigger selection and b-jet identification: a jet analysis that selects events with a b jet using a sample corresponding to an integrated luminosity of 34 inverse picobarns, and a muon analysis requiring a b jet with a muon based on an integrated luminosity of 3 inverse picobarns. In both approaches the b jets are identified by requiring a secondary vertex. The results from the two methods are in agreement with each other and with next-to-leading order calculations, as well as with predictions based on the PYTHIA event generator.

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Measurements of the associated production of a Z boson and b jets in pp collisions at sqrt(s) = 8 TeV

The CMS collaboration Khachatryan, V. ; Sirunyan, Albert M ; Tumasyan, Armen ; et al.
Eur.Phys.J.C 77 (2017) 751, 2017.
Inspire Record 1499471 DOI 10.17182/hepdata.77544

Measurements of the associated production of a Z boson with at least one jet originating from a b quark in proton-proton collisions at sqrt(s) = 8 TeV are presented. Differential cross sections are measured with data collected by the CMS experiment corresponding to an integrated luminosity of 19.8 inverse femtobarns. Z bosons are reconstructed through their decays to electrons and muons. Cross sections are measured as a function of observables characterizing the kinematics of the b jet and the Z boson. Ratios of differential cross sections for the associated production with at least one b jet to the associated production with any jet are also presented. The production of a Z boson with two b jets is investigated, and differential cross sections are measured for the dijet system. Results are compared to theoretical predictions, testing two different flavour schemes for the choice of initial-state partons.

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Measurement of the integrated and differential t-tbar production cross sections for high-pt top quarks in pp collisions at sqrt(s) = 8 TeV

The CMS collaboration Khachatryan, Vardan ; Sirunyan, Albert M ; Tumasyan, Armen ; et al.
Phys.Rev.D 94 (2016) 072002, 2016.
Inspire Record 1454211 DOI 10.17182/hepdata.78540

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.

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