Download or read book Measurement of the T Anti t Production Cross Section and Top Quark Mass Extraction Using Dilepton Events in P Anti p Collisions written by and published by . This book was released on 2009 with total page 10 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 approximately 1 fb−1 of data collected with the D0 detector. We consider decay channels containing two high p{sub T} charged leptons where one lepton is identified as an electron or a muon while the other lepton can be an electron, a muon or a hadronically decaying [tau] lepton. For a mass of the top quark of 170 GeV, the measured cross section is 7.5{sub -1.0}{sup +1.0}(stat){sub -0.06}{sup +0.7}(syst){sub -0.5}{sup 0.6}(lumi) pb. Using l{sub {tau}} events only, they measure: [sigma]{sub t{bar t}} x B(t{bar t} → l{sub {tau}}b{bar b}) = 0.13{sub -0.08}{sup +0.09}(stat){sub -0.06}{sup 0.06}(syst)+{sub -0.02}{sup +0.02}(lumi) pb. Comparing the measured cross section as a function of the mass of the top quark with a partial next-to-next-to leading order Quantum Chromodynamics theoretical prediction, we extract a mass of the top quark of 171.5{sub -8.8}{sup +9.9} GeV, in agreement with direct measurements.

Download or read book Measurement of the T Anti t Production Cross Section in P Anti p Collisions at S written by and published by . This book was released on 2007 with total page 24 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 utilizing 425 pb−1 of data collected with the D0 detector at the Fermilab Tevatron Collider. We consider the final state of the top quark pair containing one high-p{sub T} electron or muon and at least four jets. We exploit specific kinematic features of t{bar t} events to extract the cross section. For a top quark mass of 175 GeV, we measure?{sub t{bar t}} = 6.4{sub -1.2}{sup +1.3}(stat) ± 0.7(syst) ± 0.4(lum)pb, in good agreement with the standard model prediction.

Download or read book Measurement of the T Anti t Production Cross Section in P Anti p Collisions at S 1 2 written by and published by . This book was released on 2007 with total page 24 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 utilizing 425 pb−1 of data collected with the D0 detector at the Fermilab Tevatron Collider. We consider the final state of the top quark pair containing one high-p{sub T} electron or muon and at least four jets. We exploit specific kinematic features of t{bar t} events to extract the cross section. For a top quark mass of 175 GeV, we measure [sigma]{sub t{bar t}} = 6.4{sub -1.2}{sup +1.3}(stat) ± 0.7(syst) ± 0.4(lum)pb, in good agreement with the standard model prediction.

Download or read book Top Quark Pair Production written by Anna Christine Henrichs and published by Springer Science & Business Media. This book was released on 2013-10-04 with total page 231 pages. Available in PDF, EPUB and Kindle. Book excerpt: Before any kind of new physics discovery could be made at the LHC, a precise understanding and measurement of the Standard Model of particle physics' processes was necessary. The book provides an introduction to top quark production in the context of the Standard Model and presents two such precise measurements of the production of top quark pairs in proton-proton collisions at a center-of-mass energy of 7 TeV that were observed with the ATLAS Experiment at the LHC. The presented measurements focus on events with one charged lepton, missing transverse energy and jets. Using novel and advanced analysis techniques as well as a good understanding of the detector, they constitute the most precise measurements of the quantity at that time.

Download or read book A Measurement of the T Anti t Cross Section in P Anti p Collisions at S written by and published by . This book was released on 2009 with total page 43 pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper reports a measurement of the cross section for the pair production of top quarks in p{bar p} collisions at √s = 1.96 TeV at the Fermilab Tevatron. The data was collected from the CDF II detector in a set of runs with a total integrated luminosity of 1.1 fb−1. The cross section is measured in the dilepton channel, the subset of t{bar t} events in which both top quarks decay through t → Wb → l?b, where l = e,?, or?. The lepton pair is reconstructed as one identified electron or muon and one isolated track. The use of an isolated track to identify the second lepton increases the t{bar t} acceptance, particularly for the case in which one W decays as W →??. The purity of the sample may be further improved at the cost of a reduction in the number of signal events, by requiring an identified b-jet. They present the results of measurements performed with and without the request of an identified b-jet. the former is the first published CDF result for which a b-jet requirement is added to the dilepton selection. In the CDF data there are 129 pretag lepton + track candidate events, of which 69 are tagged. With the tagging information, the sample is divided into tagged and untagged sub-samples, and a combined cross section is calculated by maximizing a likelihood. The result is?{sub t{bar t}} = 9.6 ± 1.2(stat.){sub -0.5}{sup +0.6}(sys.) ± 0.6(lum.) pb, assuming a branching ratio of BR(W → l?) = 10.8% and a top mass of m{sub t} = 175 GeV/c2.

Download or read book A Measurement of the T Anti t Cross Section in P Anti p Collisions at S 1 2 written by and published by . This book was released on 2009 with total page 43 pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper reports a measurement of the cross section for the pair production of top quarks in p{bar p} collisions at √s = 1.96 TeV at the Fermilab Tevatron. The data was collected from the CDF II detector in a set of runs with a total integrated luminosity of 1.1 fb−1. The cross section is measured in the dilepton channel, the subset of t{bar t} events in which both top quarks decay through t → Wb → l[nu]b, where l = e, [mu], or [tau]. The lepton pair is reconstructed as one identified electron or muon and one isolated track. The use of an isolated track to identify the second lepton increases the t{bar t} acceptance, particularly for the case in which one W decays as W → [tau][nu]. The purity of the sample may be further improved at the cost of a reduction in the number of signal events, by requiring an identified b-jet. They present the results of measurements performed with and without the request of an identified b-jet. the former is the first published CDF result for which a b-jet requirement is added to the dilepton selection. In the CDF data there are 129 pretag lepton + track candidate events, of which 69 are tagged. With the tagging information, the sample is divided into tagged and untagged sub-samples, and a combined cross section is calculated by maximizing a likelihood. The result is [sigma]{sub t{bar t}} = 9.6 ± 1.2(stat.){sub -0.5}{sup +0.6}(sys.) ± 0.6(lum.) pb, assuming a branching ratio of BR(W → l[nu]) = 10.8% and a top mass of m{sub t} = 175 GeV/c2.

Download or read book Measurement of the T Anti t Production Cross section in P Anti p Collisions Using Dilepton Events written by and published by . This book was released on 2007 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Measurement of the P Anti p T Anti t Production Cross Section at S written by and published by . This book was released on 2006 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: A measurement of the top quark pair production cross section in proton anti-proton collisions at an interaction energy of √s = 1.96 TeV is presented. This analysis uses 405 pb−1 of data collected with the D0 detector at the Fermilab Tevatron Collider. Fully hadronic t{bar t} decays with final states of six or more jets are separated from the multijet background using secondary vertex tagging and a neural network. The t{bar t} cross section is measured as?{sub t{bar t}} = 4.5{sub -1.9}{sup +2.0}(stat){sub -1.1}{sup +1.4}(syst) ± 0.3(lumi) pb for a top quark mass of m{sub t} = 175 GeV/c2.

Download or read book Measurement of the Tanti t Production Cross Section in P Anti ptnipbar Collisions at S 1 2 written by and published by . This book was released on 2006 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: The authors present a measurement of the top quark pair production cross section in p{bar p} collisions at √s = 1.96 TeV using 318 pb−1 of data collected with the Collider Detector at Fermilab. They select t{bar t} decays into the final states e[nu] + jets and [mu][nu] + jets, in which at least one b quark from the t-quark decays is identified using a secondary vertex-finding algorithm. Assuming a top quark mass of 178 GeV/c2, they measure a cross section of 8.7 ± 0.9(stat.){sub -0.9}{sup +1.1}(syst.) pb. They also report the first observation of t{bar t} with significance greater than 5[sigma] in the subsample in which both b quarks are identified, corresponding to a cross section of 10.1{sub -1.4}{sup +1.6}(stat.){sub -1.3}{sup +2.0}(syst.) pb.

Download or read book Measurement of the T Anti t Production Cross Section in P Anti p Collisions at S 1 2 written by Heather Lynn Ray and published by . This book was released on 2004 with total page 172 pages. Available in PDF, EPUB and Kindle. Book excerpt: The direct observation of the top quark was first achieved at the Tevatron proton anti-proton collider at Fermilab. This discovery completed the third generation quark sector where the top quark is expected to accompany the bottom quark in the weak isospin doublet. This dissertation discusses the experimental verification of the production cross section as predicted by the Standard Model. A measurement of the t{bar t} production cross section using 107.9 pb{sup -1} of p{bar p} collisions at {radical}s = 1.96 TeV collected with the Collider Detector at Fermilab between March of 2003 and June of 2003 is presented. The measurement focuses on the t{bar t} production in the ''lepton plus jets'' final state in which one of the W bosons from the t{bar t} decay subsequently decays leptonically to an electron or a muon, and the other decays hadronically. The B-tagging technique which utilizes the precision silicon detector tracking is used to enhance the signal for t{bar t} events relative to the background through identification of the bottom quark from its measurable lifetime. The t{bar t} production cross section is measured to be {sigma}{sub t{bar t}} = 4.5 {+-} 1.4(stat) {+-} 0.8(sys) pb.

Download or read book Measurement of the Tanti t Production Cross Section in P Anti ptnipbar Collisions at S written by and published by . This book was released on 2006 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: The authors present a measurement of the top quark pair production cross section in p{bar p} collisions at √s = 1.96 TeV using 318 pb−1 of data collected with the Collider Detector at Fermilab. They select t{bar t} decays into the final states e? + jets and?? + jets, in which at least one b quark from the t-quark decays is identified using a secondary vertex-finding algorithm. Assuming a top quark mass of 178 GeV/c2, they measure a cross section of 8.7 ± 0.9(stat.){sub -0.9}{sup +1.1}(syst.) pb. They also report the first observation of t{bar t} with significance greater than 5? in the subsample in which both b quarks are identified, corresponding to a cross section of 10.1{sub -1.4}{sup +1.6}(stat.){sub -1.3}{sup +2.0}(syst.) pb.

Download or read book Measurement of the T Anti t Production Cross Section in P Anti p Collistions at S 1 2 written by and published by . This book was released on 2005 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: The authors present a measurement of the top quark pair (t{bar t}) production cross section in p{bar p} collisions at √s = 1.96 TeV using events with two charged leptons in the final state. This analysis utilizes an integrated luminosity of 224-243 pb−1 collected with the D0 detector at the Fermilab Tevatron Collider. They observe 13 events in the e+e−, e? and ?+ ?− channels with an expected background of 3.2 ± 0.7 events. For a top quark mass of 175 GeV, we measure a t{bar t} production cross section of ?{sub t{bar t}} = 8.6{sub -2.7}{sup +3.2}(stat) ± 1.1(syst) ± 0.6(lumi) pb, consistent with the standard model prediction.

Download or read book Measurement of the P Anti p T Anti t Production Cross Section and the Top Quark Mass at S 1 2 written by and published by . This book was released on 2007 with total page 29 pages. Available in PDF, EPUB and Kindle. Book excerpt: We report the measurements of the t{bar t} production cross section and of the top quark mass using 1.02 fb−1 of p{bar p} data collected with the CDF II detector at the Fermilab Tevatron. We select events with six or more jets on which a number of kinematical requirements are imposed by means of a neural network algorithm. At least one of these jets must be identified as initiated by a b-quark candidate by the reconstruction of a secondary vertex. The cross section is measured to be [sigma]{sub t{bar t}} = 8.3 ± 1.0(stat.){sup +2.0}{sub -1.5}(syst.) ± 0.5(lumi.) pb, which is consistent with the standard model prediction. The top quark mass of 174.0 ± 2.2(stat.)±4.8(syst.) GeV/c2 is derived from a likelihood fit incorporating reconstructed mass distributions representative of signal and background.

Download or read book Measurement of the P Anti p T Anti t Production Cross Section at S 1 2 written by and published by . This book was released on 2006 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: A measurement of the top quark pair production cross section in proton anti-proton collisions at an interaction energy of √s = 1.96 TeV is presented. This analysis uses 405 pb−1 of data collected with the D0 detector at the Fermilab Tevatron Collider. Fully hadronic t{bar t} decays with final states of six or more jets are separated from the multijet background using secondary vertex tagging and a neural network. The t{bar t} cross section is measured as [sigma]{sub t{bar t}} = 4.5{sub -1.9}{sup +2.0}(stat){sub -1.1}{sup +1.4}(syst) ± 0.3(lumi) pb for a top quark mass of m{sub t} = 175 GeV/c2.

Download or read book Measurement of the P Anti p T Anti t Production Cross Section and the Top Quark Mass at S written by and published by . This book was released on 2007 with total page 29 pages. Available in PDF, EPUB and Kindle. Book excerpt: We report the measurements of the t{bar t} production cross section and of the top quark mass using 1.02 fb−1 of p{bar p} data collected with the CDF II detector at the Fermilab Tevatron. We select events with six or more jets on which a number of kinematical requirements are imposed by means of a neural network algorithm. At least one of these jets must be identified as initiated by a b-quark candidate by the reconstruction of a secondary vertex. The cross section is measured to be?{sub t{bar t}} = 8.3 ± 1.0(stat.){sup +2.0}{sub -1.5}(syst.) ± 0.5(lumi.) pb, which is consistent with the standard model prediction. The top quark mass of 174.0 ± 2.2(stat.)±4.8(syst.) GeV/c2 is derived from a likelihood fit incorporating reconstructed mass distributions representative of signal and background.

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 704 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Physics of the Top Quark at D0 New Measurement of the Production Cross Section and Mass written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We present a measurement of the t[anti t] production cross section in p[anti p] collisions at[radical]s= 1.8 TeV and a measurement of top quark mass m[sub t] by the D0 experiment at the Fermilab Tevatron. The measurements are based on the data from the 1992- 1996 run during which the D0 detector was exposed to the integrated luminosity of approximately 125 pb[sup -1]. We observe 39 t[anti t] candidate events in the dilepton and lepton+jets decay channels with an expected background of 13.7[+-] 2.2 events. We measure the top quark mass m[sub t] using a two constraint fit to m[sub t] in t[anti t][yields] bW[sup+][anti b]W[sup -] final states with one W decaying to q[anti q] and the other to e[nu] or[mu][nu]. Events are binned in the fit mass versus a measure of probability for events to be the signal rather than a background. Likelihood fits to the data yield m[sub t]= 173.3[+-] 5.6 (stat)[+-] 6.2 (syst) GeV/c[sup 2]. For this mass we measure the t[anti t] production cross section to be 5.5[+-] 1.8 pb.