Download or read book Measurement of the t bar t Production Cross Section in the Dilepton Channel in Pp Collisions at sqrt s written by and published by . This book was released on 2013 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Erratum written by and published by . This book was released on 2014 with total page 31 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Measurement of the Top Pair Production Cross Section in the Dilepton Decay Channel in Ppbar Collisions at Sqrt S written by and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A measurement of the t{bar t} production cross section in p{bar p} collisions at √s = 1.96 TeV using events with two leptons, missing transverse energy, and jets is reported. The data were collected with the CDF II Detector. The result in a data sample corresponding to an integrated luminosity 2.8 fb−1 is: [sigma]{sub t{bar t}} = 6.27 ± 0.739(stat) ± 0.63(syst) ± 0.39(lum) pb for an assumed top mass of 175 GeV/c2.
Download or read book Measurement of the t bar t Production Cross Section in Pp Collisions at sqrt s written by and published by . This book was released on 2014 with total page 21 pages. Available in PDF, EPUB and Kindle. Book excerpt: The top-quark pair production cross section is measured in final states with one electron or muon and one hadronically decaying [tau] lepton from the process $t\bar{t}$ to (l[nu]l) ([tau][nu][tau]) $b\bar{b}$, where l = e, [mu]. The data sample corresponds to an integrated luminosity of 19.6 fb-1 collected with the CMS detector in proton-proton collisions at $\sqrt{s}$ =8 TeV. The measured cross section [sigma]$t\bar{t}$ = 257 ± 3 (stat) ± 24 (syst) ± 7 (lumi) pb, assuming a top-quark mass of 172.5 GeV, is consistent with the standard model prediction.
Download or read book Measurement of Jet Multiplicity Distributions in T T bar Production in Pp Collisions at Sqrt s written by and published by . This book was released on 2014 with total page 29 pages. Available in PDF, EPUB and Kindle. Book excerpt: The normalised differential top quark-antiquark production cross section is measured as a function of the jet multiplicity in proton-proton collisions at a centre-of-mass energy of 7 TeV at the LHC with the CMS detector. The measurement is performed in both the dilepton and lepton + jets decay channels using data corresponding to an integrated luminosity of 5.0 inverse femtobarns. Using a procedure to associate jets to decay products of the top quarks, the differential cross section of the t t-bar production is determined as a function of the additional jet multiplicity in the lepton + jets channel. Furthermore, the fraction of events with no additional jets is measured in the dilepton channel, as a function of the threshold on the jet transverse momentum. The measurements are compared with predictions from perturbative quantum chromodynamics and no significant deviations are observed.
Download or read book Measurement of the t bar t Production Cross Section Using Events with One Lepton and at Least One Jet in Pp Collisions at sqrt s written by and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A measurement of the $\mathrm{ t \bar{t} }$ production cross section at $\sqrt{s}=$ 13 TeV is presented using proton-proton collisions, corresponding to an integrated luminosity of 2.3 fb$^{-1}$, collected with the CMS detector at the LHC. Final states with one isolated charged lepton (electron or muon) and at least one jet are selected and categorized according to the accompanying jet multiplicity. From a likelihood fit to the invariant mass distribution of the isolated lepton and a jet identified as coming from the hadronization of a bottom quark, the cross section is measured to be $\sigma(\mathrm{ t \bar{t} })=$ 835 $\pm$ 3 (stat) $\pm$ 23 (syst) $\pm$ 23 (lumi) pb, in agreement with the standard model prediction. Using the expected dependence of the cross section on the pole mass of the top quark ($m_{\mathrm{ t }}$), the value of $m_{\mathrm{ t }}$ is found to be 172.7$^{+2.4}_{-2.7}$ GeV.
Download or read book Measurement of mathrm T bar t Production with Additional Jet Activity Including B Quark Jets in the Dilepton Decay Channel Using Pp Collisions at sqrt s written by and published by . This book was released on 2015 with total page 74 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Top Physics written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We present a measurement of the t{bar t} production cross section using 194 pb−1 of CDF II data using events with a high transverse momentum electron or muon, three or more jets, and missing transverse energy. The measurement assumes 100% t --> Wb branching fraction. Events consistent with t{bar t} decay are found by identifying jets containing heavy flavor semileptonic decays to muons. The dominant backgrounds are evaluated directly from the data. Based on 20 candidate events and an expected background of 9.5 " 1.1 events, we measure a production cross section of 5.3 " 3.3{sub -1.0}{sup +1.3} pb, in agreement with the standard model.
Download or read book Measurement of the Tt bar Production Cross Section in the Dilepton Channel at CDF written by Reda Tafirout and published by . This book was released on 2004 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt: We report a measurement of the t{bar t} production cross section using dilepton events with jets and missing transverse energy in p{bar p}collisions at {radical}s = 1.96 TeV. Using 197 pb{sup -1} of data recorded by the upgraded Collider Detector at Fermilab (CDF II), we use two complementary techniques to select candidate events. The combined result yields a t{bar t} production cross section of 7.0{sub -2.1}{sup +2.4}(stat){sub -1.1}{sup +1.6}(syst) {+-} 0.4(luminosity)pb which is consistent with the Standard Model.
Download or read book Measurement of the T Anti t Cross Section Using the Dimuon Channel in Ppbar Collisions at Sqrt s written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The authors have measured the t[bar t] production cross section at [radical]s = 1.96 TeV using data collected by the D0 experiment at Fermilab. The integrated luminosity of the data set is 140 pb[sup -1] and a total of four candidate events are seen, with an expected background of 2.61 events. The measured cross section of [sigma][sub t[bar t]] = 11.1[sub -9.3][sup +22.1](stat.)[sub -4.5][sup +4.3](sys.) pb is in agreement with a NNLO calculation of 6.77 pb.
Download or read book Measurement of the mathrm t bar t Production Cross Section Using Events in the mathrm e mu Final State in Pp Collisions at sqrt s written by and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The cross section of top quark-antiquark pair production in proton-proton collisions at $\sqrt{s}$ = 13 TeV is measured by the CMS experiment at the LHC, using data corresponding to an integrated luminosity of 2.2 inverse femtobarns. The measurement is performed by analyzing events in which the final state includes one electron, one muon, and two or more jets, at least one of which is identified as originating from hadronization of a b quark. The measured cross section is 792 +/- 8 (stat) +/- 37 (syst) +/- 21 (lumi) pb, in agreement with the expectation from the standard model.
Download or read book Measurement of the mathrm T bar t Production Cross Section in the mathrm E mu Channel in Proton proton Collisions at sqrt s written by and published by . This book was released on 2016 with total page 54 pages. Available in PDF, EPUB and Kindle. Book excerpt: The inclusive cross section for top quark pair production is measured in proton-proton collisions at √s = 7 and 8 TeV, corresponding to 5.0 and 19.7 fb-1, respectively, with the CMS experiment at the LHC. The cross sections are measured in the electron-muon channel using a binned likelihood fit to multi-differential final state distributions related to identified b quark jets and other jets in the event. The measured cross section values are 173.6 ± 2.1 (stat)+4.5-4.0 (syst) ± 3.8 (lumi) pb at √s = 7 TeV, and 244.9 ± 1.4 (stat)+6.3-5.5 (syst) ± 6.4 (lumi) pb at √s = 8 TeV, in good agreement with QCD calculations at next-to-next-to-leading-order accuracy. The ratio of the cross sections measured at 7 and 8 TeV is determined, as well as cross sections in the fiducial regions defined by the acceptance requirements on the two charged leptons in the final state. The cross section results are used to determine the top quark pole mass via the dependence of the theoretically predicted cross section on the mass, giving a best result of 173.8+1.7-1.8 GeV. Furthermore, the data at √s = 8 TeV are also used to set limits, for two neutralino mass values, on the pair production of supersymmetric top squarks with masses close to the top quark mass.
Download or read book Measurement of the t bar t Production Cross Section Using Dilepton Events in p bar p Collisions written by and published by . This book was released on 2011 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present a measurement of the t{bar t} production cross section [sigma]{sub t{bar t}} in p{bar p} collisions at √s = 1.96 TeV using 5.4 fb−1 of integrated luminosity collected with the D0 detector. We consider final states with at least two jets and two leptons (ee, e[mu], [mu][mu]), and events with one jet for the the e[mu] final state as well. The measured cross section is [sigma]{sub t{bar t}} = 7.36{sub -0.79}{sup +0.90} (stat + syst) pb. This result combined with the cross section measurement in the lepton + jets final state yields [sigma]{sub t{bar t}} = 7.56{sub -0.56}{sup +0.63}(stat + syst) pb, which agrees with the standard model expectation. The relative precision of 8% of this measurement is comparable to the latest theoretical calculations.
Download or read book Measurement of the Ttbar Production Cross Section in Ppbar Collisions at Sqrt s written by and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We present a measurement of the top quark pair production cross section in p{bar p} collisions at √s = 1.96 TeV using a data sample corresponding to 1.7 fb−1 of integrated luminosity collected with the Collider Detector at Fermilab. We reconstruct t{bar t} events in the lepton+jets channel, consisting of e[nu]+jets and [mu][nu]+jets final states. The dominant background is the production of W bosons in association with multiple jets. To suppress this background, we identify electrons from the semileptonic decay of heavy-flavor jets ('soft electron tags'). From a sample of 2196 candidate events, we obtain 120 tagged events with a background expectation of 51 ± 3 events, corresponding to a cross section of [sigma]{sub t{bar t}} = 7.8 ± 2.4 (stat) ± 1.6 (syst) ± 0.5 (lumi) pb. We assume a top-quark mass of 175 GeV/c2. This is the first measurement of the t{bar t} cross section with soft electron tags in Run II of the Tevatron.
Download or read book Measurements of the t bar t Charge Asymmetry Using the Dilepton Decay Channel in Pp Collisions at sqrt s written by and published by . This book was released on 2014 with total page 35 pages. Available in PDF, EPUB and Kindle. Book excerpt: The t t-bar charge asymmetry in proton-proton collisions at $\sqrt{s} =$ 7 TeV is measured using the dilepton decay channel (ee, e mu, or mu mu). The data correspond to a total integrated luminosity of 5.0 inverse femtobarns, collected by the CMS experiment at the LHC. The t t-bar and lepton charge asymmetries, defined as the differences in absolute values of the rapidities between the reconstructed top quarks and antiquarks and of the pseudorapidities between the positive and negative leptons, respectively, are measured to be Ac = -0.010 +/- 0.017 (stat.) +/- 0.008 (syst.) and Aclep = 0.009 +/- 0.010 (stat.) +/- 0.006 (syst). The lepton charge asymmetry is also measured as a function of the invariant mass, rapidity, and transverse momentum of the t t-bar system. All measurements are consistent with the expectations of the standard model.
Download or read book Large Pt Processes in Ppbar Collisions at 2 TeV written by Ashish Kumar and published by . This book was released on 2005 with total page 210 pages. Available in PDF, EPUB and Kindle. Book excerpt: The measurement of the top-antitop pair production cross section in p{bar p} collisions at {radical}s = 1.96 TeV in the dielectron decay channel using 384 pb{sup -1} of D0 data yields a t{bar t} production cross-section of {sigma}{sub t{bar t}} = 7.9{sub -3.8}{sup +5.2}(stat){sub -1.0}{sup +1.3}(syst) {+-} 0.5 (lumi) pb. This measurement [98] is based on 5 observed events with a prediction of 1.04 background events. The cross-section corresponds to the top mass of 175 GeV, and is in good agreement with the Standard Model expectation of 6.77 {+-} 0.42 pb based on next-to-next-leading-order (NNLO) perturbative QCD calculations [78]. This analysis shows significant improvement from our previous cross-section measurement in this channel [93] with 230 pb{sup -1} dataset in terms of significantly better signal to background ratio and uncertainties on the measured cross-section. Combination of all the dilepton final states [98] yields a yields a t{bar t} cross-section of {sigma}{sub t{bar t}} = 8.6{sub -2.0}{sup +2.3}(stat){sub -1.0}{sup +1.2}(syst) {+-} 0.6(lumi) pb, which again is in good agreement with theoretical predictions and with measurements in other final states. Hence, these results show no discernible deviation from the Standard Model. Fig. 6.1 shows the summary of cross-section measurements in different final states by the D0 in Run II. This measurement of cross-section in the dilepton channels is the best dilepton result from D0 till date. Previous D0 result based on analysis of 230 pb{sup -1} of data (currently under publication in Physics Letters B) is {sigma}{sub t{bar t}} = 8.6{sub -2.7}{sup +3.2}(stat){sub -1.1}{sup +1.1}(syst) {+-} 0.6(lumi) pb. It can be seen that the present cross-section suffers from less statistical uncertainty. This result is also quite consistent with CDF collaboration's result of {sigma}{sub t{bar t}} = 8.6{sub -2.4}{sup +2.5}(stat){sub -1.1}{sup +1.1}(syst) pb. These results have been presented as D0's preliminary results in the high energy physics conferences in the Summer of 2005 (Hadron Collider Physics Symposium, European Physical Society Conference, etc.). The uncertainty on the cross-section is still dominated by statistics due to the small number of observed events. It can be seen that we are at a level where statistical uncertainties are becoming closer to the systematic ones. Future measurements of the cross section will benefit from considerably more integrated luminosity, leading to a smaller statistical error. Thus the next generation of measurements will be limited by systematic uncertainties. Monte Carlo samples with higher statistics are also being generated in order to decrease the uncertainty on the background estimation. In addition, as the jet energy scale, the electron energy scale, the detector resolutions, and the luminosity measurement are fine-tuned, the systematic uncertainties will continue to decrease.
Download or read book Measurement of the T Anti t Production Cross Section in P Anti p Collisions at S 1 2 written by Lucio Cerrito and published by . This book was released on 2005 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present two measurements of the t{bar t} production cross section in collisions of protons and antiprotons at {radical}s = 196 TeV. We analyze a dataset of 310 {+-} 20 pb{sup -1} collected with the CDF 2 detector. In the first measurement, we select events with six to eight jets, at least one of which having a displaced secondary vertex, little or no missing transverse energy and optimized kinematical criteria consistent with the t{bar t} all-hadronic decay channel. In the second measurement, we select events with four or more jets, at least one of which having a displaced secondary vertex, high missing transverse energy, and optimized kinematical criteria consistent with the decay of t{bar t} to {tau}+jets. The averaged t{bar t} production cross section, determined from six different measurements using the CDF 2 detector in the dilepton, lepton+jets and all-hadronic decay channels, is also calculated to be {sigma}{sub t{bar t}} = 7.1 {+-} 0.6(stat) {+-} 0.7(syst) {+-} 0.4(lumi) pb, in agreement with the prediction of the standard model.
