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Öğe Angular coefficients of Z bosons produced in pp collisions at ?S=8 TeV and decaying to ?+?- as a function of transverse momentum and rapidity(Elsevier, 2015) Khachatryan, V.; Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Bergauer, T.; Dragicevic, M.; The CMS CollaborationMeasurements of the five most significant angular coefficients, A(0) through A(4), for Z bosons produced in pp collisions at root S = 8 TeV and decaying to mu(+)mu(-) are presented as a function of the transverse momentum and rapidity of the Z boson. The integrated luminosity of the dataset collected with the CMS detector at the LHC corresponds to 19.7 fb(-1). These measurements provide comprehensive information about the Z boson production mechanisms, and are compared to the QCD predictions at leading order, next-to-leading order, and next-to-next-to-leading order in perturbation theory. (C) 2015 CERN for the benefit of the CMS Collaboration. Published by Elsevier B.V.Öğe Combined search for anomalous pseudoscalar HW couplings in VH(H ? b(b)over-bar) production and H ? VV decay(Elsevier, 2016) Adam, W.; Asilar, E.; Bergauer, T.; Brandstetter, J.; Brondolin, E.; Dragicevic, M.; Ero, J.A search for anomalous pseudoscalar couplings of the Higgs boson H to electroweak vector bosons V (= W or Z) in a sample of proton-proton collision events corresponding to an integrated luminosity of 18.9 fb(-1) at a center-of-mass energy of 8 TeV is presented. Events consistent with the topology of associated VH production, where the Higgs boson decays to a pair of bottom quarks and the vector boson decays leptonically, are analyzed. The consistency of data with a potential pseudoscalar contribution to the HVV interaction, expressed by the effective pseudoscalar cross section fractions f(a3), is assessed by means of profile likelihood scans. Results are given for the VH channels alone and for a combined analysis of the VH and previously published H -> VV channels. Under certain assumptions, f(a3)(ZZ) > 0.0034 is excluded at 95% confidence level in the combination. Scenarios in which these assumptions are relaxed are also considered. (C) 2016 The Author. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).Öğe Constraints on parton distribution functions and extraction of the strong coupling constant from the inclusive jet cross section in pp collisions at ?s=7TeV(Springer, 2015) Khachatryan, V.; Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Bergauer, T.; Dragicevic, M.; The CMS CollaborationThe inclusive jet cross section for proton-proton collisions at a centre-of-mass energy of 7 TeV was measured by the CMS Collaboration at the LHC with data corresponding to an integrated luminosity of 5.0 fb(-1). The measurement covers a phase space up to 2 TeV in jet transverse momentum and 2.5 in absolute jet rapidity. The statistical precision of these data leads to stringent constraints on the parton distribution functions of the proton. The data provide important input for the gluon density at high fractions of the proton momentum and for the strong coupling constant at large energy scales. Using predictions from perturbative quantum chromodynamics at next-to-leading order, complemented with electroweak corrections, the constraining power of these data is investigated and the strong coupling constant at the Z boson mass M-Z is determined to be alpha(S)(M-Z) = 0.1185 +/- 0.0019 (exp)(-0.0037)(+0.0060) (theo), which is in agreement with the world average.Öğe Constraints on the Higgs boson width from off-shell production and decay to Z-boson pairs(Elsevier, 2014) Khachatryan, V.; Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Bergauer, T.; Dragicevic, M.; The CMS CollaborationConstraints are presented on the total width of the recently discovered Higgs boson, Gamma(H), using its relative on-shell and off-shell production and decay rates to a pair of Z bosons, where one Z boson decays to an electron or muon pair, and the other to an electron, muon, or neutrino pair. The analysis is based on the data collected by the CMS experiment at the LHC in 2011 and 2012, corresponding to integrated luminosities of 5.1 fb(-1) at a center-of-mass energy root s = 7 TeV and 19.7 fb(-1) at root s = 8 TeV. A simultaneous maximum likelihood fit to the measured kinematic distributions near the resonance peak and above the Z-boson pair production threshold leads to an upper limit on the Higgs boson width of Gamma(H) < 22 MeV at a 95% confidence level, which is 5.4 times the expected value in the standard model at the measured mass of m(H) = 125.6 GeV. (C) 2014 The Authors. Published by Elsevier B.V.Öğe Constraints on the pMSSM, AMSB model and on other models from the search for long-lived charged particles in proton-proton collisions at ?s=8TeV(Springer, 2015) Khachatryan, V.; Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Bergauer, T.; Dragicevic, M.; The CMS CollaborationStringent limits are set on the long-lived lepton-like sector of the phenomenological minimal supersymmetric standard model (pMSSM) and the anomaly-mediated super-symmetry breaking (AMSB) model. The limits are derived from the results presented in a recent search for long-lived charged particles in proton-proton collisions, based on data collected by the CMS detector at a centre-of-mass energy of 8 TeV at the Large Hadron Collider. In the pMSSM parameter sub-space considered, 95.9% of the points predicting charginos with a lifetime of at least 10 ns are excluded. These constraints on the pMSSM are the first obtained at the LHC. Charginos with a lifetime greater than 100 ns and masses up to about 800 GeV in the AMSB model are also excluded. The method described can also be used to set constraints on other models.Öğe Constraints on the spin-parity and anomalous HVV couplings of the Higgs boson in proton collisions at 7 and 8 TeV(Amer Physical Soc, 2015) Khachatryan, V.; Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Bergauer, T.; Dragicevic, M.; The CMS CollaborationThe study of the spin-parity and tensor structure of the interactions of the recently discovered Higgs boson is performed using the H -> ZZ, Z gamma*, gamma*gamma* -> 4l, H -> WW -> l(nu)l(nu), and H -> gamma gamma decay modes. The full data set recorded by the CMS experiment during the LHC run 1 is used, corresponding to an integrated luminosity of up to 5.1 fb(-1) at a center-of-mass energy of 7 TeV and up to 19.7 fb(-1) at 8 TeV. A wide range of spin-two models is excluded at a 99% confidence level or higher, or at a 99.87% confidence level for the minimal gravitylike couplings, regardless of whether assumptions are made on the production mechanism. Any mixed-parity spin-one state is excluded in the ZZ and WW modes at a greater than 99.999% confidence level. Under the hypothesis that the resonance is a spin-zero boson, the tensor structure of the interactions of the Higgs boson with two vector bosons ZZ, Z gamma, gamma gamma, and WW is investigated and limits on eleven anomalous contributions are set. Tighter constraints on anomalous HVV interactions are obtained by combining the HZZ and HWW measurements. All observations are consistent with the expectations for the standard model Higgs boson with the quantum numbers J(PC) = 0(++).Öğe Differential cross section measurements for the production of a W boson in association with jets in proton-proton collisions at ?s=7 TeV(Elsevier, 2015) Khachatryan, V.; Sirunyan, A. M.; Tumasyan, A. .; Adam, W.; Bergauer, T.; Dragicevic, M.; The CMS CollaborationMeasurements 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 (p(T)) and pseudorapidities of the four leading jets, the scalar sum of jet transverse momenta (H-T), 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 fb (1). 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 p(T) distributions of the leading jets at high p(T) values, the distributions of the H-T at high-H-T and low jet multiplicity, and the distribution of the difference in azimuthal angle between the leading jet and the muon at low values. (C) 2014 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/3.0/).Öğe Distributions of topological observables in inclusive three- and four-jet events in pp collisions at ?s=7 TeV(Springer, 2015) Khachatryan, V.; Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Bergauer, T.; Dragicevic, M.; The CMS CollaborationThis paper presents distributions of topological observables in inclusive three- and four-jet events produced in pp collisions at a centre-of-mass energy of 7 TeV with a data sample collected by the CMS experiment corresponding to a luminosity of 5.1 fb(-1). The distributions are corrected for detector effects, and compared with several event generators based on two- and multi-parton matrix elements at leading order. Among the considered calculations, MadGraph interfaced with PYTHIA6 displays the overall best agreement with data.Öğe Evidence for Collective Multiparticle Correlations in p-Pb Collisions(Amer Physical Soc, 2015) Khachatryan, V.; Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Bergauer, T.; Dragicevic, M.; The CMS CollaborationThe second-order azimuthal anisotropy Fourier harmonics, nu(2), are obtained in p-Pb and PbPb collisions over a wide pseudorapidity (.) range based on correlations among six or more charged particles. The p-Pb data, corresponding to an integrated luminosity of 35 nb(-1), were collected during the 2013 LHC p-Pb run at a nucleon-nucleon center-of-mass energy of 5.02 TeV by the CMS experiment. A sample of semiperipheral PbPb collision data at root S-NN = 2.76 TeV, corresponding to an integrated luminosity of 2.5 mu b(-1) and covering a similar range of particle multiplicities as the p-Pb data, is also analyzed for comparison. The six-and eight-particle cumulant and the Lee-Yang zeros methods are used to extract the nu(2) coefficients, extending previous studies of two-and four-particle correlations. For both the p-Pb and PbPb systems, the nu(2) values obtained with correlations among more than four particles are consistent with previously published four-particle results. These data support the interpretation of a collective origin for the previously observed long-range (large..) correlations in both systems. The ratios of nu(2) values corresponding to correlations including different numbers of particles are compared to theoretical predictions that assume a hydrodynamic behavior of a p-Pb system dominated by fluctuations in the positions of participant nucleons. These results provide new insights into the multiparticle dynamics of collision systems with a very small overlapping region.Öğe Identification techniques for highly boosted W bosons that decay into hadrons(Springer, 2014) Khachatryan, V.; Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Bergauer, T.; Dragicevic, M.; The CMS CollaborationIn searches for new physics in the energy regime of the LHC, it is becoming increasingly important to distinguish single-jet objects that originate from the merging of the decay products of W bosons produced with high transverse momenta from jets initiated by single partons. Algorithms are defined to identify such W jets for different signals of interest, using techniques that are also applicable to other decays of bosons to hadrons that result in a single jet, such as those from highly boosted Z and Higgs bosons. The efficiency for tagging W jets is measured in data collected with the CMS detector at a center-of-mass energy of 8TeV, corresponding to an integrated luminosity of 19.7 fb(-1). The performance of W tagging in data is compared with predictions from several Monte Carlo simulators.Öğe Long-range two-particle correlations of strange hadrons with charged particles in pPb and PbPb collisions at LHC energies(Elsevier, 2015) Khachatryan, V.; Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Bergauer, T.; Dragicevic, M.; The CMS CollaborationMeasurements of two-particle angular correlations between an identified strange hadron (K-S(0) or A/(A) over bar) and a charged particle, emitted in pPb collisions, are presented over a wide range in pseudorapidity and full azimuth. The data, corresponding to an integrated luminosity of approximately 35 nb(-1), were collected at a nucleon-nucleon center-of-mass energy (root s(NN)) of 5.02 TeV with the CMS detector at the LHC. The results are compared to semi-peripheral PbPb collision data at root s(NN) = 2.76 TeV, covering similar charged-particle multiplicities in the events. The observed azimuthal correlations at large relative pseudorapidity are used to extract the second-order (v(2)) and third-order (v(3)) anisotropy harmonics of K-S(0) and A/(A) over bar particles. These quantities are studied as a function of the charged-particle multiplicity in the event and the transverse momentum of the particles. For high-multiplicity pPb events, a clear particle species dependence of v(2) and v(3) is observed. For p(T) < 2 GeV, the v(2) and v(3) values of K-S(0) particles are larger than those of A/(A) over bar particles at the same p(T). This splitting effect between two particle species is found to be stronger in pPb than in PbPb collisions in the same multiplicity range. When divided by the number of constituent quarks and compared at the same transverse kinetic energy per quark, both v(2) and v(3) for K-S(0) particles are observed to be consistent with those for A/(A) over bar particles at the 10% level in pPb collisions. This consistency extends over a wide range of particle transverse kinetic energy and event multiplicities. (C) 2015 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license.Öğe Measurement of diffractive dissociation cross sections in pp collisions at ?s=7 TeV(Amer Physical Soc, 2015) Khachatryan, V.; Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Bergauer, T.; Dragicevic, M.; The CMS CollaborationMeasurements of diffractive dissociation cross sections in pp collisions at root s = 7 TeV are presented in kinematic regions defined by the masses M-X and M-Y of the two final-state hadronic systems separated by the largest rapidity gap in the event. Differential cross sections are measured as a function of xi= M-X(2)/s in the region -5.5 < log(10)xi 10(X) < -2.5, for logio M-Y < 0.5, dominated by single dissociation (SD), and 0.5 < log(10)M(Y) < 1.1, dominated by double dissociation (DD), where M-x and M-y are given in GeV. The inclusive pp cross section is also measured as a function of the width of the central pseudorapidity gap Delta eta for Delta eta > 3, logio M-X > 1.1, and logioMy > 1.1, a region dominated by DD. The cross sections integrated over these regions are found to be, respectively, 2.99 0.02(staf)12392(sysf) mb, 1.18 +/- 0.02(stat) +/- 0.13(syst) mh, and 0.58 +/- 0.01(stat)(-0.11)(+0.13) (syst) mh, and are used to extract extrapolated total SD and DD cross sections. In addition, the inclusive differential cross section, d sigma/d Delta eta(F), for events with a pseudorapidity gap adjacent to the edge of the detector, is measured over Delta eta F = 8.4 units of pseudorapidity. The results are compared to those of other experiments and to theoretical predictions and found compatible with slowly 'rising diffractive cross sections as a function of center-of-mass energy.Öğe Measurement of electroweak production of two jets in association with a Z boson in proton-proton collisions at ?s=8 TeV(Springer, 2015) Khachatryan, V.; Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Bergauer, T.; Dragicevic, M.; The CMS CollaborationThe purely electroweak (EW) cross section for the production of two jets in association with a Z boson, in proton-proton collisions at root s = 8 TeV, is measured using data recorded by the CMS experiment at the CERN LHC, corresponding to an integrated luminosity of 19.7 fb(-1). The electroweak cross section for the lljj final state (with l = e or mu and j representing the quarks produced in the hard interaction) in the kinematic region defined by M-ll > 50 GeV, M-jj > 120 GeV, transverse momentum p(Tj) > 25 GeV, and pseudorapidity vertical bar eta(j)vertical bar < 5, is found to be sigma(EW) (lljj) = 174 +/- 15 (stat) +/- 40 (syst) fb, in agreement with the standard model prediction. The associated jet activity of the selected events is studied, in particular in a signal-enriched region of phase space, and the measurements are found to be in agreement with QCD predictions.Öğe Measurement of J/? and ?(2S) Prompt Double-Differential Cross Sections in pp Collisions at ?s=7 TeV(Amer Physical Soc, 2015) Khachatryan, V.; Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Bergauer, T.; Dragicevic, M.; The CMS CollaborationThe double-differential cross sections of promptly produced J/psi and psi(2S) mesons are measured in pp collisions at root s = 7 TeV, as a function of transverse momentum p(T) and absolute rapidity \y\. The analysis uses J/psi and psi(2S) dimuon samples collected by the CMS experiment, corresponding to integrated luminosities of 4.55 and 4.90 fb(-1), respectively. The results are based on a two-dimensional analysis of the dimuon invariant mass and decay length, and extend to p(T) = 120 and 100 GeV for the J/psi and psi(2S), respectively, when integrated over the interval \y\ < 1.2. The ratio of the psi(2S) to J/psi cross sections is also reported for \y\ < 1.2, over the range 10 < p(T) < 100 GeV. These are the highest p(T) values for which the cross sections and ratio have been measured.Öğe Measurement of Prompt ?(2S) to J/?. Yield Ratios in Pb-Pb and p-p Collisions at ?sNN=2.76 TeV(Amer Physical Soc, 2014) Khachatryan, V.; Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Bergauer, T.; Dragicevic, M.; The CMS CollaborationThe ratio between the prompt psi (2S) and J/psi yields, reconstructed via their decays into mu(-)mu(-) is measured in Pb-Pb and p-p collisions at root sNN = 2.76 TeV. The analysis is based on Pb-Pb and p-p data samples collected by CMS at the Large Hadron Collider, corresponding to integrated luminosities of 150 mu b(-1) and 5.4 mu b(-1), respectively. The double ratio of measured yields (N phi((2S))/NJ/(Pb-Pb)/N-psi(2S)/NJ/psi)(p-p) is computed in three Pb-Pb collision centrality bins and two kinematic ranges: one at midrapidity, vertical bar y vertical bar < 1.6, covering the transverse momentum range 6.5 < pT < 30 GeV= c, and the other at forward rapidity, 1.6 < vertical bar y vertical bar < 2.4, extending to lower pT values, 3 < pT < 30 GeV/c. The centralityintegrated double ratio changes from 0.45 +/- 0.13(stat) +/- 0.07dsyst_ in the first range to 1.67 +/- 0.34(stat) +/- 0.27dsyst_ in the second. This difference is most pronounced in the most central collisions.Öğe Measurement of the cross section ratio ?t(t)over-barb(b)over-bar/?t(t)over-barjj in pp collisions at ?s=8 TeV(Elsevier, 2015) Khachatryan, V.; Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Bergauer, T.; Dragicevic, M.; The CMS CollaborationThe first measurement of the cross section ratio sigma(t (t) over barb (b) over bar)/sigma(t (t) over bar jj) is presented using a data sample corresponding to an integrated luminosity of 19.6 fb(-1) collected in pp collisions at root s = 8 TeV with the CMS detector at the LHC. Events with two leptons (e or mu) and four reconstructed jets, including two identified as b quark jets, in the final state are selected. The ratio is determined for a minimum jet transverse momentum p(T) of both 20 and 40 GeV/c. The measured ratio is 0.022 +/- 0.003 (stat) +/- 0.005 (syst) for p(T) > 20GeV/c. The absolute cross sections sigma(t (t) over barb (b) over bar) and sigma(t (t) over bar jj) are also measured. The measured ratio for p(T) > 40 GeV/c is compatible with a theoretical quantum chromodynamics calculation at next-to-leading order. (C) 2015 CERN for the benefit of the CMS Collaboration. Published by Elsevier B.V.Öğe Measurement of the differential cross section for top quark pair production in pp collisions at ?s=8TeV(Springer, 2015) Khachatryan, V.; Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Bergauer, T.; Dragicevic, M.; The CMS CollaborationThe normalized differential cross section for top quark pair (t (t) over bar) production is measured in pp collisions at a centre-of-mass energy of 8 TeV at the CERN LHC using the CMS detector in data corresponding to an integrated luminosity of 19.7 fb(-1). The measurements are performed in the lepton+jets (e/mu+jets) and in the dilepton (e(+)e(-), mu(+)mu(-), and e(+/-)mu(-/+)) decay channels. The t (t) over bar cross section is measured as a function of the kinematic properties of the charged leptons, the jets associated to b quarks, the top quarks, and the t (t) over bar system. The data are compared with several predictions from perturbative quantum chromodynamic up to approximate next-to-next-to-leading-order precision. No significant deviations are observed relative to the standard model predictions.Öğe Measurement of the inclusive 3-jet production differential cross section in proton-proton collisions at 7 TeV and determination of the strong coupling constant in the TeV range(Springer, 2015) Khachatryan, V.; Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Bergauer, T.; Dragicevic, M.; The CMS CollaborationThis paper presents a measurement of the inclusive 3-jet production differential cross section at a proton-proton centre-of-mass energy of 7 TeV using data corresponding to an integrated luminosity of 5 fb(-1) collected with the CMS detector. The analysis is based on the three jets with the highest transverse momenta. The cross section is measured as a function of the invariant mass of the three jets in a range of 445-3270 GeV and in two bins of the maximum rapidity of the jets up to a value of 2. A comparison between the measurement and the prediction from perturbative QCD at next-to-leading order is performed. Within uncertainties, data and theory are in agreement. The sensitivity of the observable to the strong coupling constant alpha(S) is studied. A fit to all data points with 3-jet masses larger than 664 GeV gives a value of the strong coupling constant of alpha(S)(M-Z) = 0.1171 +/- 0.0013 (exp) (+0.0073)(-0.0047) (theo).Öğe Measurement of the pp ? ZZ production cross section and constraints on anomalous triple gauge couplings in four-lepton final states at ?s=8 TeV(Elsevier, 2015) Khachatryan, V.; Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Bergauer, T.; Dragicevic, M.; The CMS CollaborationA measurement of the inclusive ZZ production cross section and constraints on anomalous triple gauge couplings in proton-proton collisions at root s = 8 TeV are presented. The analysis is based on a data sample, corresponding to an integrated luminosity of 19.6 fb(-1), collected with the CMS experiment at the LHC. The measurements are performed in the leptonic decay modes ZZ -> lll'l', where = e, mu and l' = e, mu, tau. The measured total cross section sigma(pp -> ZZ) = 7.7 +/- 0.5 (stat) (0)(-0.4)(+0.5) (syst) +/- 0.4 (theo) +/- 0.2 (lumi) 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(5)(Z) < 0.005, and -0.005 < f(5)(Y) < 0.005. (C) 2014 The Authors. Published by Elsevier B.V.Öğe Measurement of the production cross section ratio ?(?b2(1P))/?(?b1(1P)) in pp collisions at ?s=8TeV(Elsevier, 2015) Khachatryan, V.; Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Bergauer, T.; Dragicevic, M.; The CMS CollaborationA measurement of the production cross section ratio sigma(chi b2(1P))/sigma(chi b1(1P)) is presented. The chi b1 (1P) and chi b2 (1P) bottomonium states, promptly produced in pp collisions at root s = 8TeV, are detected by the CMS experiment at the CERN LHC through their radiative decays chi b1,2(1P) -> Y(1S) + gamma. The emitted photons are measured through their conversion to e(+) e(-) pairs, whose reconstruction allows the two states to be resolved. The Y(1S) is measured through its decay to two muons. An event sample corresponding to an integrated luminosity of 20.7 fb(-1) is used to measure the cross section ratio in a phase-space region defined by the photon pseudorapidity, vertical bar eta(gamma)vertical bar < 1.0; the Y(1S) rapidity, vertical bar y(Y)vertical bar < 1.5; and the Y(1S) transverse momentum, 7 < p(T)(Y) < 40 GeV. The cross section ratio shows no significant dependence on the.(1S) transverse momentum, with a measured average value of 0.85 +/- 0.07 (stat + syst) +/- 0.08 (BF), where the first uncertainty is the combination of the experimental statistical and systematic uncertainties and the second is from the uncertainty in the ratio of the chi b branching fractions. (C) 2015 CERN for the benefit of the CMS Collaboration. Published by Elsevier B.V.
