Measurement of normalized differential \( \mathrm{t}\overline{\mathrm{t}} \) cross sections in the dilepton channel from pp collisions at \( \sqrt{s}=13 \) TeV

HJE Measurement of normalized di erential tt cross 0 Open Access , Copyright CERN 1 production , QCD Normalized di erential cross sections for top quark pair production are measured in the dilepton (e+e , + e ) decay channels in proton-proton collisions at a center-of-mass energy of 13 TeV. The measurements are performed with data corresponding to an integrated luminosity of 2.1 fb 1 using the CMS detector at the LHC. The cross sections are measured di erentially as a function of the kinematic properties of the leptons, jets from bottom quark hadronization, top quarks, and top quark pairs at the particle and parton levels. The results are compared to several Monte Carlo generators that implement calculations up to next-to-leading order in perturbative quantum chromodynamics interfaced with parton showering, and also to xed-order theoretical calculations of top quark pair production up to next-to-next-to-leading order. Hadron-Hadron scattering (experiments); Top physics; Heavy quark - The CMS collaboration 1 Introduction 2 The CMS detector and simulation 2.1 2.2 Signal and background simulation 3 Object and event selection 4 Signal de nition 5 Reconstruction of the tt system 6 Normalized di erential cross sections 7 Systematic uncertainties 8 Results 9 Summary A Tables of di erential tt cross sections at the particle level B Tables of di erential cross section at the parton level The CMS collaboration energies of 7 [2, 3] and 8 TeV [4{12]. The dilepton (electron or muon) nal state of the tt decay helps in the suppression of background events. This paper presents the rst CMS s = 13 TeV in the dilepton decay nal state and includes the same- avor ), using data corresponding to an integrated luminosity . The statistical precision of the measurements is improved by the increased data sample from including the same- avor lepton channels. The data were recorded by the CMS experiment at the LHC in 2015, and this measurement complements other recent { 1 { measurements that have been reported in a di erent decay channel [13] and by a di erent experiment [14, 15]. The tt di erential cross section measurements are performed at the particle and parton levels. Particle-level measurements use nal-state kinematic observables that are experimentally measurable and theoretically well de ned. Corrections are limited mainly to detector e ects that can be determined experimentally. The particle-level measurements are designed to have minimal model dependencies. The visible di erential cross section is de ned for a phase space within the acceptance of the experiment. Large extrapolations into inaccessible phase-space regions are thus avoided in particle-level di erential cross section measurements. In contrast, the parton-level measurement of the top quark pair predictions of new physics beyond the standard model [16]. In addition, the normalized tt cross sections are measured as a function of the transverse momenta of the top quark and of the top quark pair. 2 2.1 The CMS detector and simulation The CMS detector The central feature of the CMS apparatus is a superconducting solenoid of 6 m internal diameter, providing a magnetic eld of 3.8 T. The solenoid volume encases the silicon pixel and strip tracker, a lead tungstate crystal electromagnetic calorimeter, and a brass and scintillator hadron calorimeter, each composed of a barrel and two endcap sections. Forward calorimeters extend the pseudorapidity ( ) coverage provided by the barrel and endcap detectors. Muons are detected in gas-ionization chambers embedded in the steel ux-return yoke outside the solenoid. A more detailed description of the CMS detector, together with a de nition of the coordinate system used and the relevant kinematic variables, can be found in ref. [17]. The particle- ow (PF) algorithm [18] is used to reconstruct objects in the event, combining information from all the CMS subdetectors. The missing transverse momentum vector (p~Tmiss) is de ned as the projection onto the plane perpendicular to the beam axis of the negative vector sum of the momenta of all PF candidates in an event [19]. Its magnitude is referred to as pTmiss. 2.2 Signal and background simulation Monte Carlo (MC) techniques are used to simulate the tt signal and the background processes. We use the powheg (v2) [20{23] generator to model the nominal tt signal at { 2 { next-to-leading order (NLO). In order to simulate tt events with additional partons, Madorder (LO) and NLO matrix elements (MEs). Parton shower (PS) simulation is performed with pythia8 (v8.205) [25], using the tune CUETP8M1 [26] to model the underlying event. Up to two partons in addition to the tt pair are calculated at NLO and combined with the pythia8 PS simulation using the FXFX [27] algorithm, denoted as MG5 amc@nlo+pythia8[FXFX]. Up to three partons are considered at LO and combined with the pythia8 PS simulation using the MLM [28] algorithm, denoted as MG5 amc@nlo+pythia8[MLM]. The data are also compared to predictions obtained with powheg samples interfaced with herwig++ [29] (v 2.7.1) using the tune EE5C [30]. The signal samples are simulated assuming a top quark mass of 172.5 GeV and normalized to the inclusive cross section calculated at NNLO precision with next-to-next-to-leadinglogarithmic (NNLL) accuracy [31]. For the simulation of W boson production and the Drell-Yan process, the MG5 amc@nlo generator is used, and the samples are normalized to the cross sections calculated at NNLO [32]. The t-channel single top quark production in the tW channel is simulated with the powheg generator based on the ve- avor scheme [33, 34], and normalized to the cross sections calculated at NNLO [35]. Diboson samples (WW, WZ, and ZZ) are simulated at LO using pythia8, and normalized to the cross section calculated at NNLO for the WW sample [36] and NLO for the WZ and ZZ samples [37]. The detector response to the nal-state particles is simulated using Geant4 [38, 39]. Additional pp collisions in the same or nearby beam crossings (pileup) are also simulated with pythia8 and superimposed on the hard-scattering events using a pileup multiplicity distribution that re ects that of the analyzed data. Simulated events are reconstructed and analyzed with the same software used to process the data. 3 Object and event selection T The dilepton nal state of the tt decay consists of two leptons (electrons or muons), at least two jets, and pmiss from the two neutrinos. Events are selected using dilepton triggers with asymmetric pT thresholds. The low transverse momentum (pT) threshold is 8 GeV for the muon and 12 GeV for the electron, and the high-pT threshold is 17 GeV for both muon and electron. The trigger e ciency is measured in data using triggers based on pmiss [40]. T The reconstructed and selected muons [41] and electrons [42] are required to have pT > 20 GeV and j j < 2:4. Since the primary leptons that originated from top quark decays are expected to be isolated, an isolation criterion is placed on each lepton to reduce the rate of secondary leptons from non-top hadronic decays. A relative isolation parameter is used, which is calculated as the sum of the pT of charged and neutral hadrons and photons in a cone of angular radius by the lepton pT, where R = p ( )2 + ( )2) around the direction of the lepton, divided and are the azimuthal and pseudorapidity di erences, respectively, between the directions of the lepton and the other particle. Any mismodeling of the lepton selection in the simulation is accounted for by applying corrections derived using a \tag-and-probe" technique based on control regions in data [43]. { 3 { Dilepton jets with pT > 30 GeV and j j < 2:4 that pass identi cation criteria designed to reject noise in the calorimeters. Jets from the hadronization of b quarks (b jets) are identi ed by the combined secondary vertex b tagging algorithm [47]. The jets are selected using a loose working point [48], corresponding to an e ciency of about 80% and a light- avor jet rejection probability of 85%. The b tagging e ciency in the simulation is corrected to be consistent with that in data. Events are required to have exactly two oppositely charged leptons with the invariant mass of the dilepton system M`+` > 20 GeV, and two or more jets, at least one of which has to be identi ed as a b jet. For the same- avor lepton channels (ee and ), additional selection criteria are applied to reject events from Drell-Yan production: pmiss > 40 GeV and jM`+` MZj > 15 GeV, where MZ is the Z boson mass [49]. The selected numbers T of events after the selection are listed in table 1. 4 Signal de nition The measurements of normalized tt di erential cross sections are performed at both particle and parton levels as a function of kinematic observables, de ned at the generator level. The particle-level top quark is de ned at the generator level using the procedure described below. This approach avoids theoretical uncertainties in the measurements due to the di erent calculations within each generator, and leads to results that are largely independent of the generator implementation and tuning. Top quarks are reconstructed in the simulation starting from the nal-state particles with a mean lifetime greater than 30 ps at the generator level, as summarized in table 2. { 4 { using all particles and ghost-B hadrons not including any neutrinos nor particles used in dressed leptons Selection criteria none pT > 20 GeV, j j < 2:4 pT > 30 GeV, j j < 2:4 with ghost-B hadrons Leptons are \dressed", which means that leptons are de ned using the anti-kT clustering algorithm [44, 45] with R = 0:1 to account for nal-state radiated photons. To avoid the ambiguity of additional leptons at the generator level, the clustering is applied to electrons, muons, and photons not from hadron decays. Events with leptons associated with lepton decays are treated as background. Leptons are required to satisfy the same acceptance requirements as imposed on the reconstructed objects described in section 3, i.e., pT > 20 GeV and j j < 2:4. The generator-level jets are clustered using the anti-kT algorithm with R = 0:4. The clustering is applied to all nal-state particles except neutrinos and particles already included in the dressed-lepton de nition. Jets are required to have pT > 30 GeV and j j < 2:4 to be consistent with the reconstructed-object selection. To identify the bottom quark avor of the jet, the ghost-B hadron technique [13] is used in which short-lifetime B hadrons are included in the jet clustering after scaling down their momentum to be negligible. A jet is identi ed as a b jet if it contains any B hadrons among its constituents. A W boson at the particle level is de ned by combining a dressed lepton and a neutrino. In each event, a pair of particle-level W bosons is chosen among the possible combinations such that the sum of the absolute values of the invariant mass di erences with respect to the W boson mass is minimal [49]. Similarly, a top quark at the particle level is de ned by combining a particle-level W boson and a b jet. The combination of a W boson and a b jet with the minimum invariant mass di erence from the correct top quark mass [49] is selected. Events are considered to be in the visible phase space if they contain a pair of particle-level top quarks, constructed from neutrinos, dressed leptons, and b jets. Simulated dilepton events that are not in the visible phase space are considered as background and combined with the non-dilepton tt decay background contribution, subsequently denoted as tt-others. In addition, the top quark and tt system observables are de ned before the top quark decays into a bottom quark and a W boson and after QCD radiation, which we refer to as the parton level. The tt system at the parton level is calculated in the generator at NLO. The normalized di erential cross sections at the parton level are derived by extrapolating the measurements into the full phase space, which includes the experimentally inaccessible regions, such as at high rapidity and low transverse momentum of the leptons and jets. { 5 { HJEP04(218)6 Reconstruction of the tt system The top quark reconstruction method is adopted from the recent CMS measurement of the di erential tt cross section [4]. In the dilepton channel, the reconstruction of the neutrino and antineutrino is crucial in measuring the top quark kinematic observables. Using an analytical approach [50, 51], the six unknown neutrino degrees of freedom are constrained by the two measured components of p~miss and the assumed invariant masses of both the W boson and top quark. The e ciency for nding a physical solution depends on the detector resolution, which is accounted for by reconstructing the tt system in both the MC simulation and data with 100 trials, using random modi cations of the measured leptons and b jets within their resolution functions. The e ciency for nding a physical solution to the kinematic reconstruction is approximately 90%, as determined from simulation and data. The numbers of events remaining after reconstructing the ttbar system are listed in table 1. In each trial, the solution with the minimum invariant mass of the tt system is selected, and a weight is calculated based on the expected invariant mass distribution of the lepton and b jet pairs (M`b) at generator level. The lepton and b jet pairs with the maximum sum of weights are chosen for the nal solution of the tt system, and the reconstructed neutrino momentum is taken from the weighted average over the trials. The kinematic variables of the leptons, b jets, top quarks, and tt system are taken from the selected nal solution. Figure 1 shows the distributions of the transverse momenta of leptons (p Tlep), jets (p Tjet), and top quarks (ptT), and the rapidity of the top quarks (yt). Figure 2 displays the distributions of the transverse momentum (ptTt), rapidity (ytt), and invariant mass (M tt) of the tt system, and the azimuthal angle between the top quarks ( tt). In the upper panel of each gure, the data points are compared to the sum of the expected contributions obtained from MC simulated events reconstructed as the data. The lower panel shows the ratio of the data to the expectations. The measured p Tlep, p Tjet, and ptT distributions are softer than those predicted by the MC simulation, resulting in the negative slopes observed in the bottom panels. However, in general, there is reasonable agreement between the data and simulation within the uncertainties, which are discussed in section 7. 6 Normalized di erential cross sections The normalized di erential tt cross sections (1= )(d =dX) are measured as a function of several di erent kinematic variables X. ytt, M tt, and tt, at both the particle and parton levels. surements are performed with p lep and p jet at the particle level. T T In addition, the mea The measurements The variables include pt , ptt, yt, T T are compared to the predictions of powheg+pythia8, MG5 amc@nlo+pythia8[FXFX], MG5 amc@nlo+pythia8[MLM], and powheg+herwig++. The non-tt backgrounds are estimated from simulation and subtracted from the data. For Drell-Yan processes the normalization of the simulation is determined from the data using the \Rout/in" method [52{54]. The non-tt backgrounds are rst subtracted from the { 6 { G 016000 C 1.40 M 1.2 taaD 00..68 1 eV 5000 CMS CMS Data tt-signal T 4000 2000 Data tt-signal distributions from data (points) and from MC simulation (shaded histograms). The signal de nition for particle level is considered to distinguish tt-signal and tt-others. All corrections described in the text are applied to the simulation. The last bin includes the over ow events. The uncertainties shown by the vertical bars on the data points are statistical only while the hatched band shows the combined statistical and systematic uncertainties added in quadrature. The lower panels display the ratios of the data to the MC prediction. { 7 { oT 1000 Data tt-signal Data tt-signal distributions from data (points) and from MC simulation (shaded histograms). The signal de nition for particle level is considered to distinguish tt-signal and tt-others. All corrections described in the text are applied to the simulation. The last bin includes the over ow events. The uncertainties shown by the vertical bars on the data points are statistical only while the hatched band shows the combined statistical and systematic uncertainties added in quadrature. The lower panels display the ratios of the data to the MC prediction. { 8 { measured distributions. The data distributions are slightly lower than those from the MC simulation. The tt-others backgrounds are then removed as a proportion of the total tt contribution by applying a single correction factor k shown in eq. (6.1), using eq. (6.2): k = N data NnMonC-tt ; NtMt-Csig + NtMt-Cothers Ntdta-stiag = N data NnMonC-tt kNtMt-Cothers: Here, NnMonC-tt is the total estimate for the non-tt background from the MC simulation, NtMt-Csig is the total MC-predicted tt signal yield, and NtMt-Cothers is the total MC prediction of the remaining tt background. The tt signal yield, Ntdta-stiag, is then extracted from the number of data events, N data, separately in each bin of the kinematic distributions, as shown in eq. (6.2). The bin widths of the distributions are chosen to control event migration between the bins at the reconstruction and generator level due to detector resolutions. We de ne the purity (stability) as the number of events generated and correctly reconstructed in a certain bin, divided by the total number of events in the reconstruction-level (generator-level) bin. The bin widths are chosen to give both a purity and a stability of about 50%. Detector resolution and reconstruction e ciency e ects are corrected using an unfolding procedure. The method relies on a response matrix that maps the expected relation between the true and reconstructed variables taken from the powheg+pythia8 simulation. The D'Agostini method [55] is employed to perform the unfolding. The e ective regularization strength of the iterative D'Agostini unfolding is controlled by the number of iterations. A small number of iterations can bias the measurement towards the simulated prediction, while with a large number of iterations the result converges to that of a matrix inversion. The number of iterations is optimized for each distribution, using simulation to nd the minimum number of iterations that reduces the bias to a negligible level. This optimization is performed with the multiplication of the response matrix and does not require any regularization. A detailed description of the method can be found in ref. [13]. (6.1) (6.2) Several sources of systematic uncertainties are studied. The normalized di erential cross sections are remeasured with respect to each source of systematic uncertainty individually, and the di erences from the nominal values in each bin are taken as the corresponding systematic uncertainty. The overall systematic uncertainties are then obtained as the quadratic sum of the individual components. The pileup distribution used in the simulation is varied by shifting the assumed total inelastic pp cross section by 5%, in order to determine the associated systematic uncertainty. The systematic uncertainties in the lepton trigger, identi cation, and isolation e ciencies are determined by varying the measured scale factors by their total uncertainties. Uncertainties coming from the jet in the jet energy scale (JES) and jet energy resolution (JER) are determined on a per-jet basis by shifting the energies of the jets [56] { 9 { within their measured energy scale and resolution uncertainties. The b tagging uncertainty is estimated by varying its e ciency uncertainty. The uncertainty in the non-tt background normalization is estimated using a 15{30% variation in the background yields, which is based on a previous CMS measurement of the tt cross section [40]. The uncertainty in the shape of the tt-others contribution is obtained by reweighting the pT distribution of the top quark for the tt-others events to match the data and comparing with the unweighted contribution. For the theoretical uncertainties, we investigate the e ect of the choice of PDFs, factorization and renormalization scales ( F and R), variation of the top quark mass, top quark pT, and hadronization and generator modeling. The PDF uncertainty is estimated using the uncertainties in the NNPDF30 NLO as 0118 set with the strong coupling strength s = 0:118 [57]. We measure 100 individual uncertainties and take the root-mean-square as the PDF uncertainty, following the PDF4LHC recommendation [58]. In addition, we consider the PDF sets with s = 0:117 and 0.119. The MC generator modeling uncertainties are estimated by taking the di erence between the results based on the powheg and MG5 amc@nlo generators. The uncertainty from the choice of F and R is estimated by varying the scales by a factor of two up and down in powheg independently for the ME and PS steps. For the ME calculation, all possible combinations are considered independently, excluding the most extreme cases of ( F, R) = (0.5, 2) and (2, 0.5) [59, 60]. The scale uncertainty in the PS modeling is assessed using dedicated MC samples with the scales varied up and down together. The uncertainties in the factorization and renormalization scales in the ME and PS calculations are taken as the envelope of the di erences with respect to the nominal parameter choice. We evaluate the top quark mass uncertainty by taking the maximum deviation between the nominal MC sample with a top quark mass of 172.5 GeV and samples with masses of 171.5 and 173.5 GeV. The tt signal cross sections are not corrected for the mismodeling of the top quark pT distribution in simulation. Instead, a systematic uncertainty from this mismodeling is obtained by comparing the nominal results to the results obtained from a response matrix using tt-signal in which the top quark pT distribution is reweighted to match the data. The uncertainty from hadronization and PS modeling is estimated by comparing the results obtained from powheg samples interfaced with pythia8 and with herwig++. Table 3 lists typical values for the statistical and systematic uncertainties in the measured normalized tt di erential cross sections. The table gives the uncertainty sources and corresponding range of the median uncertainty of each distribution, at both the particle and parton levels. The hadronization is the dominant systematic uncertainty source for ptT (4:9% at particle and 7:1% at parton level) and M tt (5:9% at particle and 7:4% at parton level), and the MC generator modeling is dominant for yt (2:3% at particle and 2:2% at parton level), ptTt (6:1% at particle and 3:9% at parton level), ytt (1:2% at particle and 1:6% at parton level), and tt (9:2% at particle and 7:3% at parton level). In general, the MC generator modeling and hadronization are the dominant systematic uncertainty sources for both the particle- and parton-level measurements. Uncertainty source Statistical Pileup modeling Trigger e ciency Lepton e ciency JES JER b jet tagging Background PDFs MC generator Fact./renorm. Top quark mass Top quark pT Hadronization | PS modeling Total systematic uncertainty Particle level [%] Parton level [%] at particle and parton levels. The uncertainty sources and the corresponding range of the median uncertainty of each distribution are shown in percent. 8 Results The normalized di erential tt cross sections are measured by subtracting the background contribution, correcting for detector e ects and acceptance, and dividing the resultant number of tt signal events by the total inclusive tt cross section. Figures 3 and 4 show the normalized di erential tt cross sections as a function of p Tlep, p Tjet, ptT, T yt, ptt, ytt, M tt, and tt at the particle level in the visible phase space. Partonlevel results are also independently extrapolated to the full phase space using the powheg+pythia8 tt simulation. Figures 5 and 6 show the normalized di erential tt cross sections as a function of ptT, yt, ptt, ytt, M tt, and T tt at parton level in the full phase space. The measured data are compared to di erent standard model predictions from powheg+pythia8, MG5 amc@nlo+pythia8[FXFX], MG5 amc@nlo+pythia8[MLM], and powheg+herwig++ in the gures. The values of the measured normalized di erential tt cross sections at the parton and particle levels with their statistical and systematic uncertainties are listed in appendices A and B. The compatibility between the measurements and the predictions is quanti ed by the high-pT region. A similar trend was also observed at p means of a 2 test performed with the full covariance matrix from the unfolding procedure, including the systematic uncertainties. Tables 4 and 5 report the values obtained for the 2 with the numbers of degrees of freedom (dof) and the corresponding p-values [61]. The lepton, jet, and top quark pT spectra in data tend to be softer than the MC predictions for s = 8 TeV by both the ATLAS HJEP04(218)6 and CMS experiments [ 4, 5 ]. The powheg+pythia8 generator better describes the ptt, yt, and ytt distributions at the particle and parton levels, while powheg+herwig++ is found to be in good agreement for the ptT at the parton and particle levels. In general, measurements are found to be in fair agreement with predictions within the uncertainties. The parton-level results are also compared to the following perturbative QCD calculations: An approximate NNLO calculation based on QCD threshold expansions beyond the leading-logarithmic approximation using the CT14nnlo PDF set [62]. An approximate next-to-NNLO (N3LO) calculation performed with the resummation of soft-gluon contributions in the double-di erential cross section at NNLL accuracy in momentum space using the MMHT2014 PDF set [63, 64]. An improved NNLL QCD calculation (NLO+NNLL') [65] with simultaneous resummation of soft and small-mass logarithms to NNLL accuracy, matched with both the standard soft-gluon resummation at NNLL accuracy and the xed-order calculation at NLO accuracy, using the MTSW2008nnlo PDF set. A full NNLO calculation based on the NNPDF3.0 PDF set [66]. The measurements and the perturbative QCD predictions are shown in gures 7 and 8. Table 6 gives the 2=dof and the corresponding p-values for the agreement between the measurements and QCD calculations. The normalized di erential tt cross sections as a function of the yt, ytt, and ptTt are found to be in good agreement with the di erent predictions considered. We observe some tension between the data and the NNLO predictions for other variables such as the ptT and M tt. 9 Summary by the CMS experiment in the dilepton decay channel in pp collisions at p The normalized di erential cross sections for top quark pair production have been presented data corresponding to an integrated luminosity of 2.1 fb 1. The di erential cross sections are measured as a function of several kinematic variables at particle level in a visible phase space corresponding to the detector acceptance and at parton level in the full phase space. The measurements are compared to the predictions from Monte Carlo simulations and calculations in perturbative quantum chromodynamics. In general, the measurements are in fairly good agreement with predictions. We con rm that the top quark pT spectrum in data is softer than the Monte Carlo predictions at both particle and parton levels, as reported by the ATLAS and CMS experiments. The present results are in agreement with the earlier ATLAS and CMS measurements. We also nd that the measurements are in better agreement with calculations within quantum chromodynamics up to next-to-next-to-leadingorder accuracy at the parton level compared to previous next-to-leading-order predictions. POWHEG H++ T plep [GeV] 2.1 fb-1 (13 TeV) POWHEG H++ t 1σ 10−3 10−4 1.4 1σ 10−3 10−4 1.4 1 1σ 10−3 10−4 1.4 ryo ta1.2 heT aD0.81 0.6 0 CMS Stat POWHEG H++ HJEP04(218)6 T 1 1 Normalized di erential tt cross sections as a function of lepton (upper left), jet (upper right), and top quark pT (lower left) and top quark rapidity (lower right), measured at the particle level in the visible phase space and combining the distributions for top quarks and antiquarks. The measured data are compared to di erent standard model predictions from powheg+pythia8 (POWHEG P8), MG5 amc@nlo+pythia8[MLM] (MG5 P8[MLM]), MG5 amc@nlo+pythia8[FXFX] (MG5 P8[FXFX]), and powheg+herwig++ (POWHEG H++). The vertical bars on the data points indicate the total (combined statistical and systematic) uncertainties while the hatched band shows the statistical uncertainty. The lower panel gives the ratio of the theoretical predictions to the data. The light-shaded band displays the combined statistical and systematic uncertainties added in quadrature. 2.1 fb-1 (13 TeV) POWHEG H++ ptTt [GeV] POWHEG H++ σ t y 1 Stat POWHEG H++ HJEP04(218)6 ytt 2.1 fb-1 (13 TeV) 1 1σ 10−3 10−4 1.4 1 d dM 1σ 10−3 10−4 1.4 ryo ta1.2 heT aD0.81 0.6 Stat+syst Stat+syst 400 600 per right), M tt (lower left), and tt (lower right), measured at the particle level in the visible phase space. The measured data are compared to di erent standard model predictions from powheg+pythia8 (POWHEG P8), MG5 amc@nlo+pythia8[MLM] (MG5 P8[MLM]), MG5 amc@nlo+pythia8[FXFX] (MG5 P8[FXFX]), and powheg+herwig++ (POWHEG H++). The vertical bars on the data points indicate the total (combined statistical and systematic) uncertainties while the hatched band shows the statistical uncertainty. The lower panel gives the ratio of the theoretical predictions to the data. The light-shaded band displays the combined statistical and systematic uncertainties added in quadrature. 1 d d 1σ 10−3 10−4 1.4 ryo ta1.2 heT aD0.81 0.6 0 CMS POWHEG H++ 500 ptT [GeV] σ t y0.55 d d 0.5 1σ CMS POWHEG H++ 100 200 300 400 quark rapidity (right), measured at the parton level in the full phase space and combining the distributions for top quarks and antiquarks. The measured data are compared to di erent standard model predictions from powheg+pythia8 (POWHEG P8), MG5 amc@nlo+pythia8[MLM] (MG5 P8[MLM]), MG5 amc@nlo+pythia8[FXFX] (MG5 P8[FXFX]), and powheg+herwig++ (POWHEG H++). The vertical bars on the data points indicate the total (combined statistical and systematic) uncertainties while the hatched band shows the statistical uncertainty. The lower panel gives the ratio of the theoretical predictions to the data. The light-shaded band displays the combined statistical and systematic uncertainties added in quadrature. 2.1 fb-1 (13 TeV) POWHEG H++ ptTt [GeV] POWHEG H++ 0.6 1 1σ 10−3 10−4 1.4 1 d d 10−4 10−5 1.4 ryo ta1.2 heT aD0.81 0.6 CMS Parton level Stat+syst Stat POWHEG H++ HJEP04(218)6 ytt 2.1 fb-1 (13 TeV) Data with stat+syst Stat POWHEG P8 MG5 P8[MLM] MG5 P8[FXFX] POWHEG H++ 1 Normalized di erential tt cross sections as a function of ptTt (upper left), ytt M tt (lower left), and tt (lower right), measured at the parton level in the full phase space. The measured data are compared to di erent standard model predictions from powheg+pythia8 (POWHEG P8), MG5 amc@nlo+pythia8[MLM] (MG5 P8[MLM]), MG5 amc@nlo+pythia8[FXFX] (MG5 P8[FXFX]), and powheg+herwig++ (POWHEG H++). The vertical bars on the data points indicate the total (combined statistical and systematic) uncertainties while the hatched band shows the statistical uncertainty. The lower panel gives the ratio of the theoretical predictions to the data. The light-shaded band displays the combined statistical and systematic uncertainties added in quadrature. <0.01 <0.01 ytt M tt tt Variable p y t T t ptt T ytt M tt tt Variable p y t T t ptt T ytt M tt powheg + pythia8 powheg + pythia8 [MLM] + pythia8 [FXFX] + herwig++ cross sections with di erent model predictions at the particle level for each of the kinematic variables. powheg + pythia8 powheg + pythia8 [MLM] + pythia8 [FXFX] + herwig++ cross sections with di erent model predictions at the parton level for each of the kinematic variables. Approx. NNLO [62] Approx. N3LO [63] NLO+NNLL' [65] NNLO [66] 2=dof cross sections with published perturbative QCD calculations. 1 V e d d 1σ 10−3 10−4 1.4 ryo ta1.2 heT aD0.81 0.6 0 CMS 100 200 300 400 quark rapidity (right), measured at the parton level in the full phase space and combining the distributions for top quarks and antiquarks. The vertical bars on the data points indicate the total (combined statistical and systematic) uncertainties, while the hatched band shows the statistical uncertainty. The measurements are compared to di erent perturbative QCD calculations of an approximate NNLO [62], an approximate next-to-NNLO (N3LO) [63], an improved NLO+NNLL (NLO+NNLL') [65], and a full NNLO [66]. The lower panel gives the ratio of the theoretical predictions to the data. Data with stat+syst Stat POWHEG P8 NNLO 1 1σ 10−3 10−4 1.4 Stat 1 V e d d 1σ 10−3 10−4 10−5 1.4 ryo ta1.2 heT aD0.81 0.6 ptTt [GeV] CMS Parton level Stat+syst σ tt y 0.6 CMS d1σ d 0.5 Parton level 0.4 0.3 0.2 0.1 0 1.4 0.6 right), and M tt (lower) for the top quarks or antiquarks, measured at parton level in the full phase space. The vertical bars on the data points indicate the total (combined statistical and systematic) uncertainties, while the hatched band shows the statistical uncertainty. 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Wolf Institute of Nuclear and Particle Physics (INPP), NCSR Demokritos, Aghia Paraskevi, Greece I. Topsis-Giotis G. Anagnostou, G. Daskalakis, T. Geralis, V.A. Giakoumopoulou, A. Kyriakis, D. Loukas, National and Kapodistrian University of Athens, Athens, Greece S. Kesisoglou, A. Panagiotou, N. Saoulidou University of Ioannina, Ioannina, Greece I. Evangelou, C. Foudas, P. Kokkas, N. Manthos, I. Papadopoulos, E. Paradas, J. Strologas, F.A. Triantis MTA-ELTE Lendulet CMS Particle and Nuclear Physics Group, Eotvos Lorand University, Budapest, Hungary M. Csanad, N. Filipovic, G. Pasztor Wigner Research Centre for Physics, Budapest, Hungary G. Bencze, C. Hajdu, D. Horvath18, F. Sikler, V. Veszpremi, G. Vesztergombi19, A.J. Zsigmond Institute of Nuclear Research ATOMKI, Debrecen, Hungary N. Beni, S. Czellar, J. Karancsi20, A. Makovec, J. Molnar, Z. Szillasi Institute of Physics, University of Debrecen, Debrecen, Hungary M. Bartok19, P. Raics, Z.L. Trocsanyi, B. Ujvari Indian Institute of Science (IISc), Bangalore, India S. Choudhury, J.R. Komaragiri National Institute of Science Education and Research, Bhubaneswar, India S. Bahinipati21, S. Bhowmik, P. Mal, K. Mandal, A. Nayak22, D.K. Sahoo21, N. Sahoo, S.K. Swain Panjab University, Chandigarh, India S. Bansal, S.B. Beri, V. Bhatnagar, U. Bhawandeep, R. Chawla, N. Dhingra, A.K. Kalsi, A. Kaur, M. Kaur, R. Kumar, P. Kumari, A. Mehta, M. Mittal, J.B. Singh, G. Walia University of Delhi, Delhi, India Ashok Kumar, Aashaq Shah, A. Bhardwaj, S. Chauhan, B.C. Choudhary, R.B. Garg, S. Keshri, A. Kumar, S. Malhotra, M. Naimuddin, K. Ranjan, R. Sharma, V. Sharma Saha Institute of Nuclear Physics, HBNI, Kolkata, India R. Bhardwaj, R. Bhattacharya, S. Bhattacharya, S. Dey, S. Dutt, S. Dutta, S. Ghosh, N. Majumdar, A. Modak, K. Mondal, S. Mukhopadhyay, S. Nandan, A. Purohit, A. Roy, D. Roy, S. Roy Chowdhury, S. Sarkar, M. Sharan, S. Thakur Indian Institute of Technology Madras, Madras, India P.K. Behera Bhabha Atomic Research Centre, Mumbai, India R. Chudasama, D. Dutta, V. Jha, V. Kumar, A.K. Mohanty14, P.K. Netrakanti, L.M. Pant, HJEP04(218)6 P. Shukla, A. Topkar Tata Institute of Fundamental Research-A, Mumbai, India T. Aziz, S. Dugad, B. Mahakud, S. Mitra, G.B. Mohanty, B. Parida, N. Sur, B. Sutar Tata Institute of Fundamental Research-B, Mumbai, India S. Banerjee, S. Bhattacharya, S. Chatterjee, P. Das, M. Guchait, Sa. Jain, S. Kumar, M. Maity23, G. Majumder, K. Mazumdar, T. Sarkar23, N. Wickramage24 Indian Institute of Science Education and Research (IISER), Pune, India S. Chauhan, S. Dube, V. Hegde, A. Kapoor, K. Kothekar, S. Pandey, A. Rane, S. Sharma Institute for Research in Fundamental Sciences (IPM), Tehran, Iran S. Chenarani25, E. Eskandari Tadavani, S.M. Etesami25, M. Khakzad, M. Mohammadi Najafabadi, M. Naseri, S. Paktinat Mehdiabadi26, F. Rezaei Hosseinabadi, B. Safarzadeh27, M. Zeinali University College Dublin, Dublin, Ireland M. Felcini, M. Grunewald INFN Sezione di Bari a, Universita di Bari b, Politecnico di Bari c, Bari, Italy M. Abbresciaa;b, C. Calabriaa;b, C. Caputoa;b, A. Colaleoa, D. Creanzaa;c, L. Cristellaa;b, N. De Filippisa;c, M. De Palmaa;b, F. Erricoa;b, L. Fiorea, G. Iasellia;c, G. Maggia;c, M. Maggia, G. Minielloa;b, S. Mya;b, S. Nuzzoa;b, A. Pompilia;b, G. Pugliesea;c, R. Radognaa;b, A. Ranieria, G. Selvaggia;b, A. Sharmaa, L. Silvestrisa;14, R. Vendittia, P. Verwilligena INFN Sezione di Bologna a, Universita di Bologna b, Bologna, Italy G. Abbiendia, C. Battilana, D. Bonacorsia;b, S. Braibant-Giacomellia;b, L. Brigliadoria;b, R. Campaninia;b, P. Capiluppia;b, A. Castroa;b, F.R. Cavalloa, S.S. Chhibraa;b, G. Codispotia;b, M. Cu ania;b, G.M. Dallavallea, F. Fabbria, A. Fanfania;b, D. Fasanellaa;b, P. Giacomellia, L. Guiduccia;b, S. Marcellinia, G. Masettia, F.L. Navarriaa;b, A. Perrottaa, A.M. Rossia;b, T. Rovellia;b, G.P. Sirolia;b, N. Tosia;b;14 INFN Sezione di Catania a, Universita di Catania b, Catania, Italy S. Albergoa;b, S. Costaa;b, A. Di Mattiaa, F. Giordanoa;b, R. Potenzaa;b, A. Tricomia;b, C. Tuvea;b INFN Sezione di Firenze a, Universita di Firenze b, Firenze, Italy G. Barbaglia, K. Chatterjeea;b, V. Ciullia;b, C. Civininia, R. D'Alessandroa;b, E. Focardia;b, P. Lenzia;b, M. Meschinia, S. Paolettia, L. Russoa;28, G. Sguazzonia, D. Stroma, L. Viliania;b;14 INFN Laboratori Nazionali di Frascati, Frascati, Italy L. Benussi, S. Bianco, F. Fabbri, D. Piccolo, F. Primavera14 INFN Sezione di Genova a, Universita di Genova b, Genova, Italy V. Calvellia;b, F. Ferroa, E. Robuttia, S. Tosia;b INFN Sezione di Milano-Bicocca a, Universita di Milano-Bicocca b, Milano, T. Tabarelli de Fatisa;b INFN Sezione di Napoli a, Universita di Napoli 'Federico II' b, Napoli, Italy, Universita della Basilicata c, Potenza, Italy, Universita G. Marconi d, Roma, S. Buontempoa, N. Cavalloa;c, S. Di Guidaa;d;14, M. Espositoa;b, F. Fabozzia;c, F. Fiengaa;b, A.O.M. Iorioa;b, W.A. Khana, G. Lanzaa, L. Listaa, S. Meolaa;d;14, P. Paoluccia;14, C. Sciaccaa;b, F. Thyssena Trento c, Trento, Italy INFN Sezione di Padova a, Universita di Padova b, Padova, Italy, Universita di P. Azzia;14, N. Bacchettaa, L. Benatoa;b, D. Biselloa;b, A. Bolettia;b, R. Carlina;b, A. Carvalho Antunes De Oliveiraa;b, P. Checchiaa, M. Dall'Ossoa;b, P. De Castro Manzanoa, T. Dorigoa, F. Gasparinia;b, U. Gasparinia;b, A. Gozzelinoa, S. Lacapraraa, M. Margonia;b, A.T. Meneguzzoa;b, M. Passaseoa, M. Pegoraroa, N. Pozzobona;b, P. Ronchesea;b, R. Rossina;b, F. Simonettoa;b, E. Torassaa, M. Zanettia;b, P. Zottoa;b INFN Sezione di Pavia a, Universita di Pavia b, Pavia, Italy A. Braghieria, F. Fallavollitaa;b, A. Magnania;b, P. Montagnaa;b, S.P. Rattia;b, V. Rea, M. Ressegotti, C. Riccardia;b, P. Salvinia, I. Vaia;b, P. Vituloa;b INFN Sezione di Perugia a, Universita di Perugia b, Perugia, Italy L. Alunni Solestizia;b, G.M. Bileia, D. Ciangottinia;b, L. Fanoa;b, P. Laricciaa;b, R. Leonardia;b, G. Mantovania;b, V. Mariania;b, M. Menichellia, A. Sahaa, A. Santocchiaa;b, D. Spiga Pisa c, Pisa, Italy INFN Sezione di Pisa a, Universita di Pisa b, Scuola Normale Superiore di K. Androsova, P. Azzurria;14, G. Bagliesia, J. Bernardinia, T. Boccalia, L. Borrello, R. Castaldia, M.A. Cioccia;b, R. Dell'Orsoa, G. Fedia, A. Giassia, M.T. Grippoa;28, F. Ligabuea;c, T. Lomtadzea, L. Martinia;b, A. Messineoa;b, F. Pallaa, A. Rizzia;b, A. SavoyNavarroa;30, P. Spagnoloa, R. Tenchinia, G. Tonellia;b, A. Venturia, P.G. Verdinia INFN Sezione di Roma a, Sapienza Universita di Roma b, Rome, Italy L. Baronea;b, F. Cavallaria, M. Cipriania;b, N. Dacia, D. Del Rea;b;14, M. Diemoza, S. Gellia;b, E. Longoa;b, F. Margarolia;b, B. Marzocchia;b, P. Meridiania, G. Organtinia;b, R. Paramattia;b, F. Preiatoa;b, S. Rahatloua;b, C. Rovellia, F. Santanastasioa;b INFN Sezione di Torino a, Universita di Torino b, Torino, Italy, Universita del Piemonte Orientale c, Novara, Italy N. Amapanea;b, R. Arcidiaconoa;c;14, S. Argiroa;b, M. Arneodoa;c, N. Bartosika, R. Bellana;b, C. Biinoa, N. Cartigliaa, F. Cennaa;b, M. Costaa;b, R. Covarellia;b, A. Deganoa;b, N. Demariaa, B. Kiania;b, C. Mariottia, S. Masellia, E. Migliorea;b, V. Monacoa;b, E. Monteila;b, M. Montenoa, M.M. Obertinoa;b, L. Pachera;b, N. Pastronea, M. Pelliccionia, G.L. Pinna Angionia;b, F. Raveraa;b, A. Romeroa;b, M. Ruspaa;c, R. Sacchia;b, K. Shchelinaa;b, V. Solaa, A. Solanoa;b, A. Staianoa, P. Traczyka;b INFN Sezione di Trieste a, Universita di Trieste b, Trieste, Italy S. Belfortea, M. Casarsaa, F. Cossuttia, G. Della Riccaa;b, A. Zanettia Kyungpook National University, Daegu, Korea D.H. Kim, G.N. Kim, M.S. Kim, J. Lee, S. Lee, S.W. Lee, Y.D. Oh, S. Sekmen, D.C. Son, Y.C. Yang A. Lee Chonbuk National University, Jeonju, Korea Chonnam National University, Institute for Universe and Elementary Particles, Kwangju, Korea H. Kim, D.H. Moon, G. Oh Hanyang University, Seoul, Korea J.A. Brochero Cifuentes, J. Goh, T.J. Kim Korea University, Seoul, Korea J. Lim, S.K. Park, Y. Roh Seoul National University, Seoul, Korea S. Cho, S. Choi, Y. Go, D. Gyun, S. Ha, B. Hong, Y. Jo, Y. Kim, K. Lee, K.S. Lee, S. Lee, J. Almond, J. Kim, J.S. Kim, H. Lee, K. Lee, K. Nam, S.B. Oh, B.C. Radburn-Smith, S.h. Seo, U.K. Yang, H.D. Yoo, G.B. Yu University of Seoul, Seoul, Korea M. Choi, H. Kim, J.H. Kim, J.S.H. Lee, I.C. Park, G. Ryu Sungkyunkwan University, Suwon, Korea Y. Choi, C. Hwang, J. Lee, I. Yu Vilnius University, Vilnius, Lithuania V. Dudenas, A. Juodagalvis, J. Vaitkus HJEP04(218)6 National Centre for Particle Physics, Universiti Malaya, Kuala Lumpur, Malaysia M.N. Yusli, Z. Zolkapli I. Ahmed, Z.A. Ibrahim, M.A.B. Md Ali31, F. Mohamad Idris32, W.A.T. Wan Abdullah, Centro de Investigacion y de Estudios Avanzados del IPN, Mexico City, Mexico H. Castilla-Valdez, E. De La Cruz-Burelo, I. Heredia-De La Cruz33, R. Lopez-Fernandez, J. Mejia Guisao, A. Sanchez-Hernandez Universidad Iberoamericana, Mexico City, Mexico S. Carrillo Moreno, C. Oropeza Barrera, F. Vazquez Valencia Benemerita Universidad Autonoma de Puebla, Puebla, Mexico I. Pedraza, H.A. Salazar Ibarguen, C. Uribe Estrada Universidad Autonoma de San Luis Potos , San Luis Potos , Mexico A. Morelos Pineda University of Auckland, Auckland, New Zealand HJEP04(218)6 D. Krofcheck P.H. Butler M. Waqas University of Canterbury, Christchurch, New Zealand National Centre for Physics, Quaid-I-Azam University, Islamabad, Pakistan A. Ahmad, M. Ahmad, Q. Hassan, H.R. Hoorani, A. Saddique, M.A. Shah, M. Shoaib, National Centre for Nuclear Research, Swierk, Poland H. Bialkowska, M. Bluj, B. Boimska, T. Frueboes, M. Gorski, M. Kazana, K. Nawrocki, K. Romanowska-Rybinska, M. Szleper, P. Zalewski Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Warsaw, Poland K. Bunkowski, A. Byszuk34, K. Doroba, A. Kalinowski, M. Konecki, J. Krolikowski, M. Misiura, M. Olszewski, A. Pyskir, M. Walczak Laboratorio de Instrumentac~ao e F sica Experimental de Part culas, Lisboa, Portugal P. Bargassa, C. Beir~ao Da Cruz E Silva, B. Calpas, A. Di Francesco, P. Faccioli, M. Gallinaro, J. Hollar, N. Leonardo, L. Lloret Iglesias, M.V. Nemallapudi, J. Seixas, O. Toldaiev, D. Vadruccio, J. Varela Joint Institute for Nuclear Research, Dubna, Russia S. Afanasiev, P. Bunin, M. Gavrilenko, I. Golutvin, I. Gorbunov, A. Kamenev, V. Karjavin, A. Lanev, A. Malakhov, V. Matveev35;36, V. Palichik, V. Perelygin, S. Shmatov, S. Shulha, N. Skatchkov, V. Smirnov, N. Voytishin, A. Zarubin Petersburg Nuclear Physics Institute, Gatchina (St. Petersburg), Russia Y. Ivanov, V. Kim37, E. Kuznetsova38, P. Levchenko, V. Murzin, V. Oreshkin, I. Smirnov, V. Sulimov, L. Uvarov, S. Vavilov, A. Vorobyev Institute for Nuclear Research, Moscow, Russia Yu. Andreev, A. Dermenev, S. Gninenko, N. Golubev, A. Karneyeu, M. Kirsanov, N. Krasnikov, A. Pashenkov, D. Tlisov, A. Toropin Institute for Theoretical and Experimental Physics, Moscow, Russia V. Epshteyn, V. Gavrilov, N. Lychkovskaya, V. Popov, I. Pozdnyakov, G. Safronov, A. Spiridonov, A. Stepennov, M. Toms, E. Vlasov, A. Zhokin HJEP04(218)6 Moscow Institute of Physics and Technology, Moscow, Russia T. Aushev, A. Bylinkin36 National Research Nuclear University 'Moscow Engineering Physics Institute' (MEPhI), Moscow, Russia M. Danilov39, P. Parygin, E. Tarkovskii P.N. Lebedev Physical Institute, Moscow, Russia V. Andreev, M. Azarkin36, I. Dremin36, M. Kirakosyan, A. Terkulov Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University, Moscow, Russia P. Volkov A. Baskakov, A. Belyaev, E. Boos, V. Bunichev, M. Dubinin40, L. Dudko, V. Klyukhin, O. Kodolova, N. Korneeva, I. Lokhtin, I. Miagkov, S. Obraztsov, M. Per lov, V. Savrin, Novosibirsk State University (NSU), Novosibirsk, Russia V. Blinov41, Y.Skovpen41, D. Shtol41 State Research Center of Russian Federation, Institute for High Energy Physics, Protvino, Russia I. Azhgirey, I. Bayshev, S. Bitioukov, D. Elumakhov, V. Kachanov, A. Kalinin, D. Konstantinov, V. Krychkine, V. Petrov, R. Ryutin, A. Sobol, S. Troshin, N. Tyurin, A. Uzunian, A. Volkov University of Belgrade, Faculty of Physics and Vinca Institute of Nuclear Sciences, Belgrade, Serbia P. Adzic42, P. Cirkovic, D. Devetak, M. Dordevic, J. Milosevic, V. Rekovic Centro de Investigaciones Energeticas Medioambientales y Tecnologicas (CIEMAT), Madrid, Spain J. Alcaraz Maestre, M. Barrio Luna, M. Cerrada, N. Colino, B. De La Cruz, A. Delgado Peris, A. Escalante Del Valle, C. Fernandez Bedoya, J.P. Fernandez Ramos, J. Flix, M.C. Fouz, P. Garcia-Abia, O. Gonzalez Lopez, S. Goy Lopez, J.M. Hernandez, M.I. Josa, A. Perez-Calero Yzquierdo, J. Puerta Pelayo, A. Quintario Olmeda, I. Redondo, L. Romero, M.S. Soares, A. Alvarez Fernandez Universidad Autonoma de Madrid, Madrid, Spain J.F. de Troconiz, M. Missiroli, D. Moran Universidad de Oviedo, Oviedo, Spain J. Cuevas, C. Erice, J. Fernandez Menendez, I. Gonzalez Caballero, J.R. Gonzalez Fernandez, E. Palencia Cortezon, S. Sanchez Cruz, I. Suarez Andres, P. Vischia, J.M. Vizan Garcia Santander, Spain Instituto de F sica de Cantabria (IFCA), CSIC-Universidad de Cantabria, I.J. Cabrillo, A. Calderon, B. Chazin Quero, E. Curras, M. Fernandez, J. Garcia-Ferrero, G. Gomez, A. Lopez Virto, J. Marco, C. Martinez Rivero, P. Martinez Ruiz del Arbol, F. Matorras, J. Piedra Gomez, T. Rodrigo, A. Ruiz-Jimeno, L. Scodellaro, N. Trevisani, I. Vila, R. Vilar Cortabitarte CERN, European Organization for Nuclear Research, Geneva, Switzerland D. Abbaneo, E. Au ray, P. Baillon, A.H. Ball, D. Barney, M. Bianco, P. Bloch, A. Bocci, C. Botta, T. Camporesi, R. Castello, M. Cepeda, G. Cerminara, E. Chapon, Y. Chen, D. d'Enterria, A. Dabrowski, V. Daponte, A. David, M. De Gruttola, A. De Roeck, E. Di Marco43, M. Dobson, B. Dorney, T. du Pree, M. Dunser, N. Dupont, A. Elliott-Peisert, P. Everaerts, G. Franzoni, J. Fulcher, W. Funk, D. Gigi, K. Gill, F. Glege, D. Gulhan, S. Gundacker, M. Gutho , P. Harris, J. Hegeman, V. Innocente, P. Janot, O. Karacheban17, J. Kieseler, H. Kirschenmann, V. Knunz, A. Kornmayer14, M.J. Kortelainen, M. Krammer1, C. Lange, P. Lecoq, C. Lourenco, M.T. Lucchini, L. Malgeri, M. Mannelli, A. Martelli, F. Meijers, J.A. Merlin, S. Mersi, E. Meschi, P. Milenovic44, F. Moortgat, M. Mulders, H. Neugebauer, S. Orfanelli, L. Orsini, L. Pape, E. Perez, M. Peruzzi, A. Petrilli, G. Petrucciani, A. Pfei er, M. Pierini, A. Racz, T. Reis, G. Rolandi45, M. Rovere, H. Sakulin, C. Schafer, C. Schwick, M. Seidel, M. Selvaggi, A. Sharma, P. Silva, P. Sphicas46, J. Steggemann, M. Stoye, M. Tosi, D. Treille, A. Triossi, A. Tsirou, V. Veckalns47, G.I. Veres19, M. Verweij, N. Wardle, W.D. Zeuner Paul Scherrer Institut, Villigen, Switzerland W. Bertly, K. Deiters, W. Erdmann, R. Horisberger, Q. Ingram, H.C. Kaestli, D. Kotlinski, U. Langenegger, T. Rohe, S.A. Wiederkehr Institute for Particle Physics, ETH Zurich, Zurich, Switzerland F. Bachmair, L. Bani, P. Berger, L. Bianchini, B. Casal, G. Dissertori, M. Dittmar, M. Donega, C. Grab, C. Heidegger, D. Hits, J. Hoss, G. Kasieczka, T. Klijnsma, W. Lustermann, B. Mangano, M. Marionneau, M.T. Meinhard, D. Meister, F. Micheli, P. Musella, F. Nessi-Tedaldi, F. Pandol , J. Pata, F. Pauss, G. Perrin, L. Perrozzi, M. Quittnat, M. Rossini, M. Schonenberger, L. Shchutska, A. Starodumov48, V.R. Tavolaro, K. Theo latos, M.L. Vesterbacka Olsson, R. Wallny, A. Zagozdzinska34, D.H. Zhu Universitat Zurich, Zurich, Switzerland T.K. Aarrestad, C. Amsler49, L. Caminada, M.F. Canelli, A. De Cosa, S. Donato, C. Galloni, A. Hinzmann, T. Hreus, B. Kilminster, J. Ngadiuba, D. Pinna, G. Rauco, P. Robmann, D. Salerno, C. Seitz, A. Zucchetta National Central University, Chung-Li, Taiwan V. Candelise, T.H. Doan, Sh. Jain, R. Khurana, M. Konyushikhin, C.M. Kuo, W. Lin, A. Pozdnyakov, S.S. Yu National Taiwan University (NTU), Taipei, Taiwan Arun Kumar, P. Chang, Y. Chao, K.F. Chen, P.H. Chen, F. Fiori, W.-S. Hou, Y. Hsiung, Y.F. Liu, R.-S. Lu, M. Min~ano Moya, E. Paganis, A. Psallidas, J.f. Tsai Chulalongkorn University, Faculty of Science, Department of Physics, Bangkok, B. Asavapibhop, K. Kovitanggoon, G. Singh, N. Srimanobhas Cukurova University, Physics Department, Science and Art Faculty, Adana, A. Adiguzel50, F. Boran, S. Cerci51, S. Damarseckin, Z.S. Demiroglu, C. Dozen, I. Dumanoglu, S. Girgis, G. Gokbulut, Y. Guler, I. Hos52, E.E. Kangal53, O. Kara, A. Kayis Topaksu, U. Kiminsu, M. Oglakci, G. Onengut54, K. Ozdemir55, D. Sunar Cerci51, H. Topakli56, S. Turkcapar, I.S. Zorbakir, C. Zorbilmez Middle East Technical University, Physics Department, Ankara, Turkey B. Bilin, G. Karapinar57, K. Ocalan58, M. Yalvac, M. Zeyrek Bogazici University, Istanbul, Turkey E. Gulmez, M. Kaya59, O. Kaya60, S. Tekten, E.A. Yetkin61 Istanbul Technical University, Istanbul, Turkey M.N. Agaras, S. Atay, A. Cakir, K. Cankocak Institute for Scintillation Materials of National Academy of Science of Ukraine, Kharkov, Ukraine B. Grynyov Kharkov, Ukraine L. Levchuk, P. Sorokin National Scienti c Center, Kharkov Institute of Physics and Technology, University of Bristol, Bristol, United Kingdom R. Aggleton, F. Ball, L. Beck, J.J. Brooke, D. Burns, E. Clement, D. Cussans, H. Flacher, J. Goldstein, M. Grimes, G.P. Heath, H.F. Heath, J. Jacob, L. Kreczko, C. Lucas, D.M. Newbold62, S. Paramesvaran, A. Poll, T. Sakuma, S. Seif El Nasr-storey, D. Smith, V.J. Smith Rutherford Appleton Laboratory, Didcot, United Kingdom K.W. Bell, A. Belyaev63, C. Brew, R.M. Brown, L. Calligaris, D. Cieri, D.J.A. Cockerill, J.A. Coughlan, K. Harder, S. Harper, E. Olaiya, D. Petyt, C.H. Shepherd-Themistocleous, A. Thea, I.R. Tomalin, T. Williams Imperial College, London, United Kingdom M. Baber, R. Bainbridge, S. Breeze, O. Buchmuller, A. Bundock, S. Casasso, M. Citron, D. Colling, L. Corpe, P. Dauncey, G. Davies, A. De Wit, M. Della Negra, R. Di Maria, P. Dunne, A. Elwood, D. Futyan, Y. Haddad, G. Hall, G. Iles, T. James, R. Lane, C. Laner, L. Lyons, A.-M. Magnan, S. Malik, L. Mastrolorenzo, T. Matsushita, J. Nash, A. Nikitenko48, J. Pela, M. Pesaresi, D.M. Raymond, A. Richards, A. Rose, E. Scott, C. Seez, A. Shtipliyski, S. Summers, A. Tapper, K. Uchida, M. Vazquez Acosta64, T. Virdee14, D. Winterbottom, J. Wright, S.C. Zenz Brunel University, Uxbridge, United Kingdom J.E. Cole, P.R. Hobson, A. Khan, P. Kyberd, I.D. Reid, P. Symonds, L. Teodorescu, Baylor University, Waco, U.S.A. A. Borzou, K. Call, J. Dittmann, K. Hatakeyama, H. Liu, N. Pastika Catholic University of America, Washington DC, U.S.A. R. Bartek, A. Dominguez The University of Alabama, Tuscaloosa, U.S.A. A. Buccilli, S.I. Cooper, C. Henderson, P. Rumerio, C. West Boston University, Boston, U.S.A. D. Arcaro, A. Avetisyan, T. Bose, D. Gastler, D. Rankin, C. Richardson, J. Rohlf, L. Sulak, D. Zou D. Yu Brown University, Providence, U.S.A. G. Benelli, D. Cutts, A. Garabedian, J. Hakala, U. Heintz, J.M. Hogan, K.H.M. Kwok, E. Laird, G. Landsberg, Z. Mao, M. Narain, J. Pazzini, S. Piperov, S. Sagir, R. Syarif, University of California, Davis, Davis, U.S.A. R. Band, C. Brainerd, D. Burns, M. Calderon De La Barca Sanchez, M. Chertok, J. Conway, R. Conway, P.T. Cox, R. Erbacher, C. Flores, G. Funk, M. Gardner, W. Ko, R. Lander, C. Mclean, M. Mulhearn, D. Pellett, J. Pilot, S. Shalhout, M. Shi, J. Smith, M. Squires, D. Stolp, K. Tos, M. Tripathi, Z. Wang University of California, Los Angeles, U.S.A. M. Bachtis, C. Bravo, R. Cousins, A. Dasgupta, A. Florent, J. Hauser, M. Ignatenko, N. Mccoll, D. Saltzberg, C. Schnaible, V. Valuev University of California, Riverside, Riverside, U.S.A. E. Bouvier, K. Burt, R. Clare, J. Ellison, J.W. Gary, S.M.A. Ghiasi Shirazi, G. Hanson, J. Heilman, P. Jandir, E. Kennedy, F. Lacroix, O.R. Long, M. Olmedo Negrete, M.I. Paneva, A. Shrinivas, W. Si, H. Wei, S. Wimpenny, B. R. Yates University of California, San Diego, La Jolla, U.S.A. J.G. Branson, G.B. Cerati, S. Cittolin, M. Derdzinski, R. Gerosa, B. Hashemi, A. Holzner, D. Klein, G. Kole, V. Krutelyov, J. Letts, I. Macneill, M. Masciovecchio, D. Olivito, S. Padhi, M. Pieri, M. Sani, V. Sharma, S. Simon, M. Tadel, A. Vartak, S. Wasserbaech65, J. Wood, F. Wurthwein, A. Yagil, G. Zevi Della Porta University of California, Santa Barbara - Department of Physics, Santa Barbara, U.S.A. N. Amin, R. Bhandari, J. Bradmiller-Feld, C. Campagnari, A. Dishaw, V. Dutta, M. Franco Sevilla, C. George, F. Golf, L. Gouskos, J. Gran, R. Heller, J. Incandela, S.D. Mullin, A. Ovcharova, H. Qu, J. Richman, D. Stuart, I. Suarez, J. Yoo California Institute of Technology, Pasadena, U.S.A. D. Anderson, J. Bendavid, A. Bornheim, J.M. Lawhorn, H.B. Newman, T. Nguyen, C. Pena, M. Spiropulu, J.R. Vlimant, S. Xie, Z. Zhang, R.Y. Zhu Carnegie Mellon University, Pittsburgh, U.S.A. M.B. Andrews, T. Ferguson, T. Mudholkar, M. Paulini, J. Russ, M. Sun, H. Vogel, I. Vorobiev, M. Weinberg University of Colorado Boulder, Boulder, U.S.A. J.P. Cumalat, W.T. Ford, F. Jensen, A. Johnson, M. Krohn, S. Leontsinis, T. Mulholland, K. Stenson, S.R. Wagner Cornell University, Ithaca, U.S.A. J. Alexander, J. Chaves, J. Chu, S. Dittmer, K. Mcdermott, N. Mirman, J.R. Patterson, A. Rinkevicius, A. Ryd, L. Skinnari, L. So , S.M. Tan, Z. Tao, J. Thom, J. Tucker, P. Wittich, M. Zientek Fermi National Accelerator Laboratory, Batavia, U.S.A. S. Abdullin, M. Albrow, G. Apollinari, A. Apresyan, A. Apyan, S. Banerjee, L.A.T. Bauerdick, A. Beretvas, J. Berryhill, P.C. Bhat, G. Bolla, K. Burkett, J.N. Butler, A. Canepa, H.W.K. Cheung, F. Chlebana, M. Cremonesi, J. Duarte, V.D. Elvira, J. Freeman, Z. Gecse, E. Gottschalk, L. Gray, D. Green, S. Grunendahl, O. Gutsche, R.M. Harris, S. Hasegawa, J. Hirschauer, Z. Hu, B. Jayatilaka, S. Jindariani, M. Johnson, U. Joshi, B. Klima, B. Kreis, S. Lammel, D. Lincoln, R. Lipton, M. Liu, T. Liu, R. Lopes De Sa, J. Lykken, K. Maeshima, N. Magini, J.M. Marra no, S. Maruyama, D. Mason, P. McBride, P. Merkel, S. Mrenna, S. Nahn, V. O'Dell, K. Pedro, O. Prokofyev, G. Rakness, L. Ristori, B. Schneider, E. Sexton-Kennedy, A. Soha, W.J. Spalding, L. Spiegel, S. Stoynev, J. Strait, N. Strobbe, L. Taylor, S. Tkaczyk, N.V. Tran, L. Uplegger, E.W. Vaandering, C. Vernieri, M. Verzocchi, R. Vidal, M. Wang, H.A. Weber, A. Whitbeck University of Florida, Gainesville, U.S.A. D. Acosta, P. Avery, P. Bortignon, A. Brinkerho , A. Carnes, M. Carver, D. Curry, S. Das, R.D. Field, I.K. Furic, J. Konigsberg, A. Korytov, K. Kotov, P. Ma, K. Matchev, H. Mei, G. Mitselmakher, D. Rank, D. Sperka, N. Terentyev, L. Thomas, J. Wang, S. Wang, J. Yelton Florida International University, Miami, U.S.A. Y.R. Joshi, S. Linn, P. Markowitz, G. Martinez, J.L. Rodriguez Florida State University, Tallahassee, U.S.A. A. Ackert, T. Adams, A. Askew, S. Hagopian, V. Hagopian, K.F. Johnson, T. Kolberg, T. Perry, H. Prosper, A. Santra, R. Yohay Florida Institute of Technology, Melbourne, U.S.A. M.M. Baarmand, V. Bhopatkar, S. Colafranceschi, M. Hohlmann, D. Noonan, T. Roy, F. Yumiceva University of Illinois at Chicago (UIC), Chicago, U.S.A. M.R. Adams, L. Apanasevich, D. Berry, R.R. Betts, R. Cavanaugh, X. Chen, O. Evdokimov, C.E. Gerber, D.A. Hangal, D.J. Hofman, K. Jung, J. Kamin, I.D. Sandoval Gonzalez, M.B. Tonjes, H. Trauger, N. Varelas, H. Wang, Z. Wu, J. Zhang The University of Iowa, Iowa City, U.S.A. B. Bilki66, W. Clarida, K. Dilsiz67, S. Durgut, R.P. Gandrajula, M. Haytmyradov, V. Khristenko, J.-P. Merlo, H. Mermerkaya68, A. Mestvirishvili, A. Moeller, J. Nachtman, H. Ogul69, Y. Onel, F. Ozok70, A. Penzo, C. Snyder, E. Tiras, J. Wetzel, K. Yi Johns Hopkins University, Baltimore, U.S.A. B. Blumenfeld, A. Cocoros, N. Eminizer, D. Fehling, L. Feng, A.V. Gritsan, P. Maksimovic, J. Roskes, U. Sarica, M. Swartz, M. Xiao, C. You The University of Kansas, Lawrence, U.S.A. A. Al-bataineh, P. Baringer, A. Bean, S. Boren, J. Bowen, J. Castle, S. Khalil, A. Kropivnitskaya, D. Majumder, W. Mcbrayer, M. Murray, C. Royon, S. Sanders, E. Schmitz, R. Stringer, J.D. Tapia Takaki, Q. Wang Kansas State University, Manhattan, U.S.A. A. Ivanov, K. Kaadze, Y. Maravin, A. Mohammadi, L.K. Saini, N. Skhirtladze, S. Toda Lawrence Livermore National Laboratory, Livermore, U.S.A. F. Rebassoo, D. Wright University of Maryland, College Park, U.S.A. C. Anelli, A. Baden, O. Baron, A. Belloni, B. Calvert, S.C. Eno, C. Ferraioli, N.J. Hadley, S. Jabeen, G.Y. Jeng, R.G. Kellogg, J. Kunkle, A.C. Mignerey, F. Ricci-Tam, Y.H. Shin, A. Skuja, S.C. Tonwar Massachusetts Institute of Technology, Cambridge, U.S.A. D. Abercrombie, B. Allen, V. Azzolini, R. Barbieri, A. Baty, R. Bi, S. Brandt, W. Busza, I.A. Cali, M. D'Alfonso, Z. Demiragli, G. Gomez Ceballos, M. Goncharov, D. Hsu, Y. Iiyama, G.M. Innocenti, M. Klute, D. Kovalskyi, Y.S. Lai, Y.-J. Lee, A. Levin, P.D. Luckey, B. Maier, A.C. Marini, C. Mcginn, C. Mironov, S. Narayanan, X. Niu, C. Paus, C. Roland, G. Roland, J. Salfeld-Nebgen, G.S.F. Stephans, K. Tatar, D. Velicanu, J. Wang, T.W. Wang, B. Wyslouch University of Minnesota, Minneapolis, U.S.A. A.C. Benvenuti, R.M. Chatterjee, A. Evans, P. Hansen, S. Kalafut, Y. Kubota, Z. Lesko, J. Mans, S. Nourbakhsh, N. Ruckstuhl, R. Rusack, J. Turkewitz University of Mississippi, Oxford, U.S.A. J.G. Acosta, S. Oliveros University of Nebraska-Lincoln, Lincoln, U.S.A. E. Avdeeva, K. Bloom, D.R. Claes, C. Fangmeier, R. Gonzalez Suarez, R. Kamalieddin, I. Kravchenko, J. Monroy, J.E. Siado, G.R. Snow, B. Stieger State University of New York at Bu alo, Bu alo, U.S.A. M. Alyari, J. Dolen, A. Godshalk, C. Harrington, I. Iashvili, D. Nguyen, A. Parker, S. Rappoccio, B. Roozbahani Northeastern University, Boston, U.S.A. G. Alverson, E. Barberis, A. Hortiangtham, A. Massironi, D.M. Morse, D. Nash, T. Orimoto, R. Teixeira De Lima, D. Trocino, R.-J. Wang, D. Wood Northwestern University, Evanston, U.S.A. S. Bhattacharya, O. Charaf, K.A. Hahn, N. Mucia, N. Odell, B. Pollack, M.H. Schmitt, K. Sung, M. Trovato, M. Velasco University of Notre Dame, Notre Dame, U.S.A. N. Dev, M. Hildreth, K. Hurtado Anampa, C. Jessop, D.J. Karmgard, N. Kellams, K. Lannon, N. Loukas, N. Marinelli, F. Meng, C. Mueller, Y. Musienko35, M. Planer, A. Reinsvold, R. Ruchti, G. Smith, S. Taroni, M. Wayne, M. Wolf, A. Woodard The Ohio State University, Columbus, U.S.A. J. Alimena, L. Antonelli, B. Bylsma, L.S. Durkin, S. Flowers, B. Francis, A. Hart, C. Hill, W. Ji, B. Liu, W. Luo, D. Puigh, B.L. Winer, H.W. Wulsin Princeton University, Princeton, U.S.A. A. Benaglia, S. Cooperstein, O. Driga, P. Elmer, J. Hardenbrook, P. Hebda, D. Lange, J. Luo, D. Marlow, K. Mei, I. Ojalvo, J. Olsen, C. Palmer, P. Piroue, D. Stickland, A. Svyatkovskiy, C. Tully University of Puerto Rico, Mayaguez, U.S.A. S. Malik, S. Norberg Purdue University, West Lafayette, U.S.A. A. Barker, V.E. Barnes, S. Folgueras, L. Gutay, M.K. Jha, M. Jones, A.W. Jung, A. Khatiwada, D.H. Miller, N. Neumeister, J.F. Schulte, J. Sun, F. Wang, W. Xie Purdue University Northwest, Hammond, U.S.A. T. Cheng, N. Parashar, J. Stupak Rice University, Houston, U.S.A. A. Adair, B. Akgun, Z. Chen, K.M. Ecklund, F.J.M. Geurts, M. Guilbaud, W. Li, B. Michlin, M. Northup, B.P. Padley, J. Roberts, J. Rorie, Z. Tu, J. Zabel University of Rochester, Rochester, U.S.A. A. Bodek, P. de Barbaro, R. Demina, Y.t. Duh, T. Ferbel, M. Galanti, A. Garcia-Bellido, J. Han, O. Hindrichs, A. Khukhunaishvili, K.H. Lo, P. Tan, M. Verzetti The Rockefeller University, New York, U.S.A. R. Ciesielski, K. Goulianos, C. Mesropian Rutgers, The State University of New Jersey, Piscataway, U.S.A. A. Agapitos, J.P. Chou, Y. Gershtein, T.A. Gomez Espinosa, E. Halkiadakis, M. Heindl, E. Hughes, S. Kaplan, R. Kunnawalkam Elayavalli, S. Kyriacou, A. Lath, R. Montalvo, K. Nash, M. Osherson, H. Saka, S. Salur, S. Schnetzer, D. She eld, S. Somalwar, R. Stone, S. Thomas, P. Thomassen, M. Walker University of Tennessee, Knoxville, U.S.A. M. Foerster, J. Heideman, G. Riley, K. Rose, S. Spanier, K. Thapa Texas A&M University, College Station, U.S.A. O. Bouhali71, A. Castaneda Hernandez71, A. Celik, M. Dalchenko, M. De Mattia, A. Delgado, S. Dildick, R. Eusebi, J. Gilmore, T. Huang, T. Kamon72, R. Mueller, Y. Pakhotin, R. Patel, A. Perlo , L. Pernie, D. Rathjens, A. Safonov, A. Tatarinov, K.A. Ulmer Texas Tech University, Lubbock, U.S.A. N. Akchurin, J. Damgov, F. De Guio, P.R. Dudero, J. Faulkner, E. Gurpinar, S. Kunori, K. Lamichhane, S.W. Lee, T. Libeiro, T. Peltola, S. Undleeb, I. Volobouev, Z. Wang Vanderbilt University, Nashville, U.S.A. S. Greene, A. Gurrola, R. Janjam, W. Johns, C. Maguire, A. Melo, H. Ni, P. Sheldon, S. Tuo, J. Velkovska, Q. Xu University of Virginia, Charlottesville, U.S.A. sith, X. Sun, Y. Wang, E. Wolfe, F. Xia Wayne State University, Detroit, U.S.A. C. Clarke, R. Harr, P.E. Karchin, J. Sturdy, S. Zaleski M.W. Arenton, P. Barria, B. Cox, R. Hirosky, A. Ledovskoy, H. Li, C. Neu, T. SinthupraUniversity of Wisconsin - Madison, Madison, WI, U.S.A. J. Buchanan, C. Caillol, S. Dasu, L. Dodd, S. Duric, B. Gomber, M. Grothe, M. Herndon, A. Herve, U. Hussain, P. Klabbers, A. Lanaro, A. Levine, K. Long, R. Loveless, G.A. Pierro, G. Polese, T. Ruggles, A. Savin, N. Smith, W.H. Smith, D. Taylor, N. Woods y: Deceased China 1: Also at Vienna University of Technology, Vienna, Austria 2: Also at State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing, 3: Also at Universidade Estadual de Campinas, Campinas, Brazil 4: Also at Universidade Federal de Pelotas, Pelotas, Brazil 5: Also at Universite Libre de Bruxelles, Bruxelles, Belgium 6: Also at Joint Institute for Nuclear Research, Dubna, Russia 7: Also at Helwan University, Cairo, Egypt 8: Now at Zewail City of Science and Technology, Zewail, Egypt 9: Now at Fayoum University, El-Fayoum, Egypt 11: Now at Ain Shams University, Cairo, Egypt 12: Also at Universite de Haute Alsace, Mulhouse, France 13: Also at Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University, Moscow, Russia 14: Also at CERN, European Organization for Nuclear Research, Geneva, Switzerland 15: Also at RWTH Aachen University, III. Physikalisches Institut A, Aachen, Germany 16: Also at University of Hamburg, Hamburg, Germany 17: Also at Brandenburg University of Technology, Cottbus, Germany 18: Also at Institute of Nuclear Research ATOMKI, Debrecen, Hungary 19: Also at MTA-ELTE Lendulet CMS Particle and Nuclear Physics Group, Eotvos Lorand University, Budapest, Hungary 20: Also at Institute of Physics, University of Debrecen, Debrecen, Hungary 21: Also at Indian Institute of Technology Bhubaneswar, Bhubaneswar, India 22: Also at Institute of Physics, Bhubaneswar, India 23: Also at University of Visva-Bharati, Santiniketan, India 24: Also at University of Ruhuna, Matara, Sri Lanka 25: Also at Isfahan University of Technology, Isfahan, Iran 26: Also at Yazd University, Yazd, Iran 27: Also at Plasma Physics Research Center, Science and Research Branch, Islamic Azad University, Tehran, Iran 28: Also at Universita degli Studi di Siena, Siena, Italy 29: Also at INFN Sezione di Milano-Bicocca; Universita di Milano-Bicocca, Milano, Italy 30: Also at Purdue University, West Lafayette, U.S.A. 31: Also at International Islamic University of Malaysia, Kuala Lumpur, Malaysia 32: Also at Malaysian Nuclear Agency, MOSTI, Kajang, Malaysia 33: Also at Consejo Nacional de Ciencia y Tecnolog a, Mexico city, Mexico 34: Also at Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland 35: Also at Institute for Nuclear Research, Moscow, Russia 36: Now at National Research Nuclear University 'Moscow Engineering Physics Institute' (MEPhI), Moscow, Russia 37: Also at St. Petersburg State Polytechnical University, St. Petersburg, Russia 38: Also at University of Florida, Gainesville, U.S.A. 39: Also at P.N. Lebedev Physical Institute, Moscow, Russia 40: Also at California Institute of Technology, Pasadena, U.S.A. 41: Also at Budker Institute of Nuclear Physics, Novosibirsk, Russia 42: Also at Faculty of Physics, University of Belgrade, Belgrade, Serbia 43: Also at INFN Sezione di Roma; Sapienza Universita di Roma, Rome, Italy Belgrade, Serbia 45: Also at Scuola Normale e Sezione dell'INFN, Pisa, Italy 46: Also at National and Kapodistrian University of Athens, Athens, Greece 47: Also at Riga Technical University, Riga, Latvia 48: Also at Institute for Theoretical and Experimental Physics, Moscow, Russia 49: Also at Albert Einstein Center for Fundamental Physics, Bern, Switzerland 50: Also at Istanbul University, Faculty of Science, Istanbul, Turkey 51: Also at Adiyaman University, Adiyaman, Turkey 52: Also at Istanbul Aydin University, Istanbul, Turkey 44: Also at University of Belgrade, Faculty of Physics and Vinca Institute of Nuclear Sciences, 54: Also at Cag University, Mersin, Turkey 55: Also at Piri Reis University, Istanbul, Turkey 56: Also at Gaziosmanpasa University, Tokat, Turkey 57: Also at Izmir Institute of Technology, Izmir, Turkey 58: Also at Necmettin Erbakan University, Konya, Turkey 59: Also at Marmara University, Istanbul, Turkey 60: Also at Kafkas University, Kars, Turkey 61: Also at Istanbul Bilgi University, Istanbul, Turkey 62: Also at Rutherford Appleton Laboratory, Didcot, United Kingdom 63: Also at School of Physics and Astronomy, University of Southampton, Southampton, United 64: Also at Instituto de Astrof sica de Canarias, La Laguna, Spain 65: Also at Utah Valley University, Orem, U.S.A. 66: Also at Beykent University, Istanbul, Turkey 67: Also at Bingol University, Bingol, Turkey 68: Also at Erzincan University, Erzincan, Turkey 69: Also at Sinop University, Sinop, Turkey 70: Also at Mimar Sinan University, Istanbul, Istanbul, Turkey 71: Also at Texas A&M University at Qatar, Doha, Qatar 72: Also at Kyungpook National University, Daegu, Korea q 2000 p MG5 P8[MLM] MG5 P8[FXFX] MG5 P8[MLM] MG5 P8[FXFX] MG5 P8[MLM] MG5 P8[FXFX] MG5 P8[MLM] MG5 P8[FXFX] MG5 P8[MLM] MG5 P8[FXFX] MG5 P8[MLM] MG5 P8 [FXFX] t σ t MG5 P8[MLM] MG5 P8[FXFX] MG5 P8[MLM] MG5 P8[FXFX] MG5 P8[MLM] MG5 P8[FXFX] MG5 P8[MLM] MG5 P8[FXFX] MG5 P8[MLM] MG5 P8 [FXFX] [29] M. Bahr et al., HERWIG++ physics and manual , Eur. Phys. J. C 58 ( 2008 ) 639 [33] S. Frixione , E. Laenen, P. Motylinski , B.R. Webber and C.D. White , Single-top [49] Particle Data Group collaboration, C. Patrignani et al., Review of particle physics , Chin. [50] L. Sonnenschein , Analytical solution of tt dilepton equations , Phys. Rev. D 73 ( 2006 ) 054015