Read Books Online and Download eBooks, EPub, PDF, Mobi, Kindle, Text Full Free.
Measurement Of The Top Quark Production Cross Section In Proton Antiproton Collisions At 18 Tev Center Of Mass Energy
Download Measurement Of The Top Quark Production Cross Section In Proton Antiproton Collisions At 18 Tev Center Of Mass Energy full books in PDF, epub, and Kindle. Read online Measurement Of The Top Quark Production Cross Section In Proton Antiproton Collisions At 18 Tev Center Of Mass Energy ebook anywhere anytime directly on your device. Fast Download speed and no annoying ads. We cannot guarantee that every ebooks is available!
Book Synopsis Measurement of the Top Quark Production Cross Section in Proton-antiproton Collisions at 1.8 TeV Center of Mass Energy by : Peter Dominic Tamburello
Download or read book Measurement of the Top Quark Production Cross Section in Proton-antiproton Collisions at 1.8 TeV Center of Mass Energy written by Peter Dominic Tamburello and published by . This book was released on 1998 with total page 256 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Measurement of the Top Quark Pair Production Cross-section in Dimuon Final States in Proton-antiproton Collisions at 1.96 TeV. by :
Download or read book Measurement of the Top Quark Pair Production Cross-section in Dimuon Final States in Proton-antiproton Collisions at 1.96 TeV. written by and published by . This book was released on 2008 with total page 181 pages. Available in PDF, EPUB and Kindle. Book excerpt: Particle physics deals with the fundamental building blocks of matter and their interactions. The vast number of subatomic particles can be reduced to twelve fundamental fermions, which interact by the exchange of spin-1 particles as described in the Standard Model (SM) of particle physics. The SM provides the best description of the subatomic world to date, despite the fact it does not include gravitation. Following the relation [lambda] = h/p, where h is Planck's constant, for the examination of physics at subatomic scales with size [lambda] probes with high momenta p are necessary. These high energies are accessible through particle colliders. Here, particles are accelerated and brought to collision at interaction points at which detectors are installed to record these particle collisions. Until the anticipated start-up of the Large Hadron Collider at CERN, the Tevatron collider at Fermilab near Chicago is the highest energy collider operating in the world, colliding protons and anti-protons at a center-of-mass energy of √s = 1.96 TeV. Its two interaction points are covered by the multi purpose particle detectors D0 and CDF. During the first data-taking period, known as Run I, the Tevatron operated at a center-of-mass energy of 1.8 TeV. This run period lasted from 1992 to 1996. During this period, the long-predicted top quark was discovered. From 1996 and 2001, the accelerator was upgraded to deliver higher instantaneous luminosities at its current center-of-mass energy. At the same time, the experiments were upgraded to take full advantage of the upgraded accelerator complex. The Tevatron is currently the only accelerator in the world with a sufficient energy to produce top quarks. Studying top quark production, decay and properties is an important part of the D0 and CDF physics programs. Because of its large mass, the top quark is a unique probe of the Standard Model, and an interesting environment to search for new physics. In this thesis, a measurement of the production cross-section of top quark pairs decaying to two muons is presented. In addition, a Monte Carlo study of the top quark spin correlation measurement was carried out. This thesis is laid out as follows: chapter two gives a short overview over the Standard Model of particle physics and the theoretical aspects of unpolarized and polarized top quark production and decay, chapter three describes the accelerator complex and the D0 experiment whose data is used in this analysis. The Reconstruction of events recorded with the D0 detector is explained in chapter four and the data and Monte Carlo samples used are presented in chapter five. Finally, the cross-section measurement is described in chapter six and the Monte Carlo study of top quark spin correlations in chapter seven.
Book Synopsis Measurement of the Top Quark Pair Production Cross Section in Proton-antiproton Collisions at a Center of Mass Energy of 1.96 TeV, Hadronic Top Decays with the D0 Detector by :
Download or read book Measurement of the Top Quark Pair Production Cross Section in Proton-antiproton Collisions at a Center of Mass Energy of 1.96 TeV, Hadronic Top Decays with the D0 Detector written by and published by . This book was released on 2009 with total page 193 pages. Available in PDF, EPUB and Kindle. Book excerpt: Of the six quarks in the standard model the top quark is by far the heaviest: 35 times more massive than its partner the bottom quark and more than 130 times heavier than the average of the other five quarks. Its correspondingly small decay width means it tends to decay before forming a bound state. Of all quarks, therefore, the top is the least affected by quark confinement, behaving almost as a free quark. Its large mass also makes the top quark a key player in the realm of the postulated Higgs boson, whose coupling strengths to particles are proportional to their masses. Precision measurements of particle masses for e.g. the top quark and the W boson can hereby provide indirect constraints on the Higgs boson mass. Since in the standard model top quarks couple almost exclusively to bottom quarks (t 2!Wb), top quark decays provide a window on the standard model through the direct measurement of the Cabibbo-Kobayashi-Maskawa quark mixing matrix element V{sub tb}. In the same way any lack of top quark decays into W bosons could imply the existence of decay channels beyond the standard model, for example charged Higgs bosons as expected in two-doublet Higgs models: t 2!Hb. Within the standard model top quark decays can be classified by the (lepton or quark) W boson decay products. Depending on the decay of each of the W bosons, t{bar t} pair decays can involve either no leptons at all, or one or two isolated leptons from direct W 2!e{bar {nu}}{sub e} and W 2![mu]{bar {nu}}{sub {mu}} decays. Cascade decays like b 2!Wc 2!e{bar {nu}}{sub e}c can lead to additional non-isolated leptons. The fully hadronic decay channel, in which both Ws decay into a quark-antiquark pair, has the largest branching fraction of all t{bar t} decay channels and is the only kinematically complete (i.e. neutrino-less) channel. It lacks, however, the clear isolated lepton signature and is therefore hard to distinguish from the multi-jet QCD background. It is important to measure the cross section (or branching fraction) in each channel independently to fully verify the standard model. Top quark pair production proceeds through the strong interaction, placing the scene for top quark physics at hadron colliders. This adds an additional challenge: the huge background from multi-jet QCD processes. At the Tevatron, for example, t{bar t} production is completely hidden in light q{bar q} pair production. The light (i.e. not bottom or top) quark pair production cross section is six orders of magnitude larger than that for t{bar t} production. Even including the full signature of hadronic t{bar t} decays, two b-jets and four additional jets, the QCD cross section for processes with similar signature is more than five times larger than for t{bar t} production. The presence of isolated leptons in the (semi)leptonic t{bar t} decay channels provides a clear characteristic to distinguish the t{bar t} signal from QCD background but introduces a multitude of W- and Z-related backgrounds.
Author :Anna Christine Henrichs Publisher :Springer Science & Business Media ISBN 13 :3319014870 Total Pages :231 pages Book Rating :4.3/5 (19 download)
Book Synopsis Top Quark Pair Production by : Anna Christine Henrichs
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.
Book Synopsis Measurement of the Single Top Production Cross Section in Proton-antiproton Collisions at 1.96 TeV. by :
Download or read book Measurement of the Single Top Production Cross Section in Proton-antiproton Collisions at 1.96 TeV. written by and published by . This book was released on 2010 with total page 342 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis describes a search for singly produced top quarks via an electroweak vertex in head-on proton-antiproton collisions at a center of mass energy of √s = 1.96 TeV. The analysis uses a total of 2.3 fb−1 of data collected with the D0 detector at Fermilab, corresponding to two different run periods of the Tevatron collider. Two channels contribute to single top quark production at the Tevatron, the s-channel and the t-channel. In the s-channel, a virtual W boson is produced from the aniquilation of a quark and an antiquark and a top and a bottom quarks are produced from the W decay. The top quark decays almost exclusively into a W boson and a bottom quark. Final states are considered in which the W boson decays leptonically into an electron or a muon plus a neutrino. Thus, at the detector level, the final state characterizing the s-channel contains one lepton, missing energy accounting for the neutrino, and two jets from the two bottom quarks. In the t-channel, the final state has an additional jet coming from a light quark. Clearly, a precise reconstruction of the events requires a precise measurement of the energy of the jets. A multivariate technique, Bayesian neural networks, is used to extract the single top signal from the overwhelming background still left after event selection. A Bayesian likelihood probability is then computed to measure the single top cross section. Assuming the observed excess is due to single top events, the measured single top quark production cross section is [sigma](p{bar p} → tb + X, tqb + X) = 4.70{sub -0.93}{sup +1.18} pb. The observed excess is associated with a p-value of (3.2 ± 2.3) x 10−8, assuming the background-only hypothesis. This p-value corresponds to an excess over background of 5.4 standard deviations for a Gaussian density. The p-value computed using the standard model signal cross section of 3.46 pb is (22.7 ± 0.6) x 10−6, corresponding to an expected significance of 4.08 standard deviations.
Book Synopsis Recueil. Festival d'Edimbourg.1947 by :
Download or read book Recueil. Festival d'Edimbourg.1947 written by and published by . This book was released on 1949 with total page 48 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Measurement of the Single Top Quark Cross Section in the Lepton Plus Jets Final State in Proton-Antiproton Collisions at a Center of Mass Energy of 1.96 TeV Using the CDF II Detector by :
Download or read book Measurement of the Single Top Quark Cross Section in the Lepton Plus Jets Final State in Proton-Antiproton Collisions at a Center of Mass Energy of 1.96 TeV Using the CDF II Detector written by and published by . This book was released on 2012 with total page 222 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present a measurement of the single top quark cross section in the lepton plus jets final state using an integrated luminosity corresponding to 7.5 fb-1 of p\bar p collision data collected by the Collider Detector at Fermilab. The single top candidate events are identified by the signature of a charged lepton, large missing transverse energy, and two or three jets with at least one of them identified as originating from a bottom quark. A new Monte Carlo generator POWHEG is used to model the single top quark production processes, which include s-channel, t-channel, and Wt-channel. A neural network multivariate method is exploited to discriminate the single top quark signal from the comparatively large backgrounds. We measure a single top production cross section of $3.04^{+0.57}_{-0.53} (\mathrm{stat.~+~syst.})$ pb assuming $m_{\rm top}=172.5$~GeV/$c^2$. In addition, we extract the CKM matrix element value $
Book Synopsis Measurement of the Single Top Quark Production Cross Section and [math Display by :
Download or read book Measurement of the Single Top Quark Production Cross Section and [math Display written by and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Measurement of the Single Top Quark Production Cross Section and by :
Download or read book Measurement of the Single Top Quark Production Cross Section and written by and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: An updated measurement of the single top quark production cross section is presented using the full data set collected by the Collider Detector at Fermilab (CDF), corresponding to 9.5 fb-1 of integrated luminosity from proton-antiproton collisions at 1.96 TeV center-of-mass energy. The events selected contain an imbalance in the total transverse momentum, jets identified as containing b quarks, and no identified leptons. The sum of the s- and t-channel single top quark cross sections is measured to be 3.53-1.16+1.25 pb and a lower limit on the magnitude of the top-to-bottom quark coupling,
Book Synopsis Measurements of the Top Quark at the Tevatron Collider by :
Download or read book Measurements of the Top Quark at the Tevatron Collider written by and published by . This book was released on 2007 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: The authors present recent preliminary measurements of the top-antitop pair production cross section and determinations of the top quark pole mass, performed using the data collected by the CDF and D0 Collaborations at the Tevatron Collider. In the lepton plus jets final state, with semileptonic B decay, the pair production cross section has now been measured at CDF using (almost equal to) 760 pb−1 of proton-antiproton collisions at a center-of-mass energy of (square root)s = 1.96 TeV. A measurement of the production cross section has also been made with (almost equal to) 1 fb−1 of data in the all-jets final state by the CDF Collaboration. The mass of the top quark has now been measured using (almost equal to) 1 fb−1 of collision data using all decay channels of the top quark pair, yielding the most precise measurements of the top mass to date.
Book Synopsis Top-Quark Pair Production Cross Sections and Calibration of the Top-Quark Monte-Carlo Mass by : Jan Kieseler
Download or read book Top-Quark Pair Production Cross Sections and Calibration of the Top-Quark Monte-Carlo Mass written by Jan Kieseler and published by Springer. This book was released on 2016-06-15 with total page 172 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis presents the first experimental calibration of the top-quark Monte-Carlo mass. It also provides the top-quark mass-independent and most precise top-quark pair production cross-section measurement to date. The most precise measurements of the top-quark mass obtain the top-quark mass parameter (Monte-Carlo mass) used in simulations, which are partially based on heuristic models. Its interpretation in terms of mass parameters used in theoretical calculations, e.g. a running or a pole mass, has been a long-standing open problem with far-reaching implications beyond particle physics, even affecting conclusions on the stability of the vacuum state of our universe. In this thesis, this problem is solved experimentally in three steps using data obtained with the compact muon solenoid (CMS) detector. The most precise top-quark pair production cross-section measurements to date are performed. The Monte-Carlo mass is determined and a new method for extracting the top-quark mass from theoretical calculations is presented. Lastly, the top-quark production cross-sections are obtained – for the first time – without residual dependence on the top-quark mass, are interpreted using theoretical calculations to determine the top-quark running- and pole mass with unprecedented precision, and are fully consistently compared with the simultaneously obtained top-quark Monte-Carlo mass.
Book Synopsis Measurement of the Top-antitop Quark Pair Differential Cross Section with Respect to the Invariant Mass of the Pair in Proton-antiproton Collisions at a Center of Mass Energy of 1.96 TeV. by :
Download or read book Measurement of the Top-antitop Quark Pair Differential Cross Section with Respect to the Invariant Mass of the Pair in Proton-antiproton Collisions at a Center of Mass Energy of 1.96 TeV. written by and published by . This book was released on 2008 with total page 125 pages. Available in PDF, EPUB and Kindle. Book excerpt: I present a measurement of the t{bar t} differential cross section, d[sigma]/dM{sub t{bar t}}, in p{bar p} collisions at √s = 1.96 TeV using 2.7 fb−1 of CDF II data. I find that d[sigma]/dM{sub t{bar t}} is consistent with the Standard Model expectation, as modeled by PYTHIA with CTEQ5L parton distribution functions. I set limits on the ratio [kappa]/M{sub Pl} in the Randall-Sundrum model by looking for Kaluza Klein gravitons which decay to top quarks. I find [kappa]/M{sub Pl} > 0.16 at the 95% confidence level.
Book Synopsis First Measurement of the Top-quark Pair Production Cross Section in Proton-proton Collisions at the Center of Mass Energy of 7 TeV by : Puneeth D. Kalavase
Download or read book First Measurement of the Top-quark Pair Production Cross Section in Proton-proton Collisions at the Center of Mass Energy of 7 TeV written by Puneeth D. Kalavase and published by . This book was released on 2011 with total page 167 pages. Available in PDF, EPUB and Kindle. Book excerpt: The first measurement of the cross section for top-quark pair production in proton-proton collisions at the Large Hadron Collider at center-of-mass energy of 7 TeV has been performed using a data sample corresponding to an integrated luminosity of 3 pb-1 recorded by the CMS detector. This result utilizes the final state with two isolated, highly energetic charged leptons, large missing transverse energy, and two or more jets. Backgrounds from Drell-Yan and non-W/Z boson production are estimated from data. Eleven events are observed in the data with 2.1+/-1.0 events expected from background. The measured cross section is 194+/-72 (statistical) +/-24 (systematic) +/-21 (luminosity) pb. The result is consistent with next-to-leading order theoretical predictions.
Book Synopsis Top Quark-anti-top Quark Production Cross Section Measurement Using Soft Electron Tagging in Proton-anti-proton Collisions at Center of Mass Energy by : John Paul Chou
Download or read book Top Quark-anti-top Quark Production Cross Section Measurement Using Soft Electron Tagging in Proton-anti-proton Collisions at Center of Mass Energy written by John Paul Chou and published by . This book was released on 2008 with total page 474 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis A Measurement of the Top-antitop Production Cross Section in Proton-antiproton Collisions at Center of Mass Energy by : Ulysses Allen Grundler
Download or read book A Measurement of the Top-antitop Production Cross Section in Proton-antiproton Collisions at Center of Mass Energy written by Ulysses Allen Grundler and published by ProQuest. This book was released on 2008 with total page 119 pages. Available in PDF, EPUB and Kindle. Book excerpt: I present a measurement of the tt¯ production cross section at s = 1.96 TeV using 2034 pb-1 of CDF Run II data using events with a high transverse momentum electron or muon, three or more jets, and missing transverse energy. The measurement assumes a t → Wb branching fraction of 100 percent. Events consistent with tt¯ decay are found by identifying jets containing heavy-flavor semileptonic decays to muons. The dominant backgrounds are evaluated directly from the data. Based on 248 candidate events and an expected background of 86.8+/-5.6 events, I measure a production cross section of 8.7+/-1.1+0.9-0.8+/-0.6 pb, in agreement with the Standard Model.
Book Synopsis A Measurement of the Production Cross Section of Top-antitop Pairs in Proton-antiproton Collisions at a Center of Mass of 1.96 TeV Using Secondary Vertexb-tagging by : Henri Bachacou
Download or read book A Measurement of the Production Cross Section of Top-antitop Pairs in Proton-antiproton Collisions at a Center of Mass of 1.96 TeV Using Secondary Vertexb-tagging written by Henri Bachacou and published by . This book was released on 2004 with total page 232 pages. Available in PDF, EPUB and Kindle. Book excerpt: A measurement of the t{bar t} pair production cross section is presented using 162 pb{sup -1} of data collected by the CDF experiment during Run II at the Tevatron. t{bar t} events in the lepton+jets channel are isolated by identifying electrons and muons, reconstructing jets and transverse missing energy, and identifying b jets with a secondary vertex tagging algorithm. The efficiency of the algorithm is measured in a control sample using a novel technique that is less dependent on the simulation. For a top quark mass of 175 GeV/c{sup 2}, a cross section of {sigma}{sub t{bar t}} = 5.6{sub -1.1}{sup +1.2}(stat.){sub -0.6}{sup +0.9}(syst.)pb is measured.
Book Synopsis Study on the Top Quark Pair Production Mechanism in 1.96 TeV Proton-antiproton Collisions by :
Download or read book Study on the Top Quark Pair Production Mechanism in 1.96 TeV Proton-antiproton Collisions written by and published by . This book was released on 2008 with total page 159 pages. Available in PDF, EPUB and Kindle. Book excerpt: The study of the top quark pair production mechanism in proton-antiproton collisions at a center-of-mass energy of 1.96 TeV is described. The main subjects are the measurements of the top quark pair production cross section, the top quark mass and a search for a new particle decaying to the top quark pair. The analyses are based on 1.9 fb−1 of data collected by the Collider Detector at Fermilab (CDF) Run II experiment between March 2002 and May 2007, using the lepton+jets events. The measured top quark pair production cross section is 8.2 ± 0.5 (stat.) ± 0.8 (syst.) ± 0.5 (lum.) pb, which is slightly higher than the standard model prediction at the top mass of 175 GeV/c2. The top quark mass is an important parameter in the standard model, and also in the experimental studies. The measured top quark mass if 171.6 ± 2.0 (stat.) ± 1.3(syst.) GeV/c2. Finally, they report on a search for a new gauge boson decaying to t{bar t}, which interferes with the standard model gluon in the q{bar q} --> t{bar t} production process. They call such a hypothetical particle a 'Massive Gluon'. The observed t{bar t} invariant mass distribution is consistent with the standard model expectations, and also the measured massive gluon coupling strength with quarks is consistent within a statistical fluctuation of the standard model expectation in the wide range of the massive gluon masses and widths. They set the upper and lower limits on the coupling strength of the massive gluon.
