Download or read book Spin Correlation in T anti T Production from P anti P Collisions At radical written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The Standard Model predicts that the lifetime of the top quark is shorter than the typical time scale at which hadronization process occurs, and the spin information at its production is preserved. Spin correlation of the t[anti t] system from p[anti p] collisions at the Tevatron is analyzed using 6 events in the dilepton channels collected using the D0 detector. Spin correlation factor of[kappa]>[minus] 0.25 at 68% CL is obtained from the data.
Download or read book Spin Correlation in T anti T Production from P anti P Collisions at s written by and published by . This book was released on 2000 with total page 331 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Standard Model predicts that the lifetime of the top quark is shorter than the typical time scale at which hadronization process occurs, and the spin information at its production is preserved. Spin correlation of the t{anti t} system from p{anti p} collisions at the Tevatron is analyzed using 6 events in the dilepton channels collected using the D0 detector. Spin correlation factor of?> - 0.25 at 68% CL is obtained from the data.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 376 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.
Download or read book J psi Production in P anti P Collisions At radical written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The authors have studied J/[psi] production in p[anti p] collisions at[radical]s= 1.8 TeV with the D0 detector at Fermilab, using a[mu][sup+][mu][sup[minus]] data sample corresponding to an integrated luminosity of 13 pb[sup[minus]1]. They have measured the inclusive J/[psi] production cross section as a function of J/[psi] transverse momentum p[sub T]. For the kinematic range p[sub T]> 8 GeV/c and[vert-bar][eta][vert-bar]
Download or read book Measurement of Spin Correlations in Top Anti Top Events from Pp Collisions at Sqrt s written by and published by . This book was released on 2014 with total page 249 pages. Available in PDF, EPUB and Kindle. Book excerpt: The top quark decays before it hadronises. Before its spin state can be changed in a process of strong interaction, it is directly transferred to the top quark decay products. The top quark spin can be deduced by studying angular distributions of the decay products. The Standard Model predicts the top/anti-top quark (tt) pairs to have correlated spins. The degree is sensitive to the spin and the production mechanisms of the top quark. Measuring the spin correlation allows to test the predictions. New physics e ects can be reflected in deviations from the prediction. In this thesis the spin ...
Download or read book Evidence for Spin Correlation in t bar t Production written by and published by . This book was released on 2011 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present a measurement of the ratio of events with correlated t and {bar t} spins to the total number of t{bar t} events. This ratio f is evaluated using a matrix-element-based approach in events with a single lepton (electron or muon) and at least four jets. We analyze p{bar p} collisions data corresponding to an integrated luminosity of 5.3 fb−1 collected with the D0 detector at the Fermilab Tevatron collider operating at a center of mass energy √s = 1.96 TeV. Combining this result with a recent measurement of f in t{bar t} → W+b W−{bar b} → l+ [nu]b l− {bar {nu}}b final states, we find f in agreement with the standard model. In addition, the combination provides evidence for the presence of spin correlation in t{bar t} events with a significance of more than three standard deviations.
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 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 A Measurement of the T Anti t Production Cross section in Proton Anti proton Collisions at S 1 2 written by Markus Klute and published by . This book was released on 2004 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt: A preliminary measurement of the t{bar t} production cross section at {radical}s = 1.96 TeV is presented. The {mu}-plus-jets final state is analyzed in a data sample of 94 pb{sup -1} and a total of 14 events are selected with a background expectation of 11.7 {+-} 1.9 events. The measurement yields: {sigma}{sub p{bar p} {yields} t{bar t} + X} = 2.4{sub -3.5}{sup +4.2}(stat.){sub -2.6}{sup +2.5}(syst.) {+-} 0.3(lumi.) pb. The analysis, being part of a larger effort to re-observe the top quark in Tevatron Run II data and to measure the production cross section, is combined with results from all available analyses channels. The combined result yields: {sigma}{sub p{bar p}} {yields} t{bar t} + X = 8.1{sub -2.0}{sup +2.2}(stat.){sub -1.4}{sup +1.6}(syst.) {+-} 0.8(lumi.) pb.
Download or read book Nuclear Science Abstracts written by and published by . This book was released on 1976-06 with total page 1216 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Search for Resonant T Anti t Production in P Anti p Collisions at S 1 2 written by and published by . This book was released on 2007 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Spin Correlations in Tt Events from Pp Collisions written by Boris Lemmer and published by . This book was released on 2015 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis introduces readers to the Standard Model, the top quark and its properties, before explaining the concept of spin correlation measurement. The first measurement of top quark spin correlations at the LHC in the lepton+jets decay channel is presented. As the heaviest elementary particle, the top quark plays an essential role in the Standard Model of elementary particle physics. In the case of top quarks being produced in pairs at hadron colliders, the Standard Model predicts their spins to be correlated. The degree of correlation depends on both the production mechanism and properties of the top quark. Any deviation from the Standard Model prediction can be an indicator for new physics phenomena. The thesis employs an advanced top quark reconstruction algorithm including dedicated identification of the up- and down-type quarks from the W boson decay.
Download or read book Measurement of Spin Correlations in T tbar Production Using the Matrix Element Method in the Muon jets Final State in Pp Collisions at u221A s written by and published by . This book was released on 2016 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt: The consistency of the spin correlation strength in top quark pair production with the standard model (SM) prediction is tested in the muon+jets final state. The events are selected from pp collisions, collected by the CMS detector, at a centre-of-mass energy of 8 TeV, corresponding to an integrated luminosity of 19.7 fb-1. We then compare the data with the expectation for the spin correlation predicted by the SM and with the expectation of no correlation. Furthermore, by using a template fit method, the fraction of events that show SM spin correlations is measured to be 0.72 ±0.08 (stat)+0.15 -0.13 (syst), representing the most precise measurement of this quantity in the lepton+jets final state to date.
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 2005 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present a measurement of the top quark pair (t{bar t}) production cross section ([sigma]{sub t{bar t}}) in p{bar p} collisions at a center-of-mass energy of 1.96 TeV using 230 pb1 of data collected by the D0 detector at the Fermilab Tevatron Collider. We select events with one charged lepton (electron or muon), large missing transverse energy, and at least four jets, and extract the t{bar t} content of the sample based on the kinematic characteristics of the events. For a top quark mass of 175 GeV, we measure [sigma]{sub t{bar t}} = 6.7{sub -1.3}{sup +1.4}(stat){sub -1.1}{sup +1.6}(syst) ± 0.4(lumi)pb, in good agreement with the standard model prediction.
Download or read book A Search for T anti T yields Lepton E sub T Jets Signature in P anti P Collisions at radical 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 report the results from a search for t[anti t] production in p[anti p] collisions at [radical]s = 1.8 TeV with the D0 detector at Fermilab in the final states consisting of one isolated high p[sub T] lepton (e or [mu]), multiple jets and a substantial missing transverse energy (E[sub T]), excluding the events that have [mu]-tagged jets. Two independent analysis approaches lead them to similar estimates for the cross-section. They see no conclusive evidence for top production in the 13.5 pb[sup [minus]1] of data taken during the 1992--1993 run of the Tevatron.
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 t bar t Helicity Fractions and Spin Correlation in p bar p 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:
