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A Precision Measurement Of The Top Quark Mass
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Book Synopsis A Precision Measurement of the Top Quark Mass by : Kevin Matthew Black
Download or read book A Precision Measurement of the Top Quark Mass written by Kevin Matthew Black and published by . This book was released on 2005 with total page 226 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation describes the measurement of the top quark mass using events recorded during a {approx} 230 pb{sup -1} exposure of the D0 detector to proton-anti-proton (p{bar p}) collisions at a center of mass energy of 1.96 TeV. The Standard Model of particle physics predicts that the top quark will decay into a bottom quark and a W boson close to 100% of the time. The bottom quark will hadronize (bind with another quark) and produce a jet of hadronic particles. The W bosons can decay either into a charged lepton and a neutrino or a pair of quarks. this dissertation focuses on the top quark (t{bar t}) events in which one W decays hadronically and the other decays leptonically. Two methods of identifying t{bar t} events from the large number of events produced are used. The first is based on the unique topology of the final state particles of a heavy particle. By using the topological information of the event, the t{bar t} events can be efficiently extracted from the background. The second method relies on the identification of the remnants of the long lived bottom quarks that are expected to be produced in the decay of almost every top quark. Because the largest background processes do not contain bottom quarks, this is an extremely efficient way to select the events retaining about 60% of the t{bar t} events and removing almost 90% of the background. A kinematic fit to the top quark mass is performed on the t{bar t} candidate events using the final state particles that are seen in the detector. A likelihood technique is then used to extract the most likely value of the top quark mass, m{sub t}, and signal fraction. The result for the topological selection is m{sub t} = 169.9 {+-} 5.8(statistical){sub -7.8}{sup +8.0}(systematic) GeV while the results on the sample selected from identification of a b quark in the event is m{sub t} = 170.6 {+-} 4.2(statistical){sub -6.8}{sup +6.3}(systematic) GeV.
Book Synopsis Precision Measurement of Top Quark Mass at by :
Download or read book Precision Measurement of Top Quark Mass at written by and published by . This book was released on 2014 with total page 86 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Precision Top-Quark Mass Measurements at CDF. by :
Download or read book Precision Top-Quark Mass Measurements at CDF. written by and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We present a precision measurement of the top-quark mass using the full sample of Tevatron √s = 1.96 TeV proton-antiproton collisions collected by the CDF II detector, corresponding to an integrated luminosity of 8.7 fb−1. Using a sample of t{bar t} candidate events decaying into the lepton+jets channel, we obtain distributions of the top-quark masses and the invariant mass of two jets from the W boson decays from data. We then compare these distributions to templates derived from signal and background samples to extract the top-quark mass and the energy scale of the calorimeter jets with in situ calibration. The likelihood fit of the templates from signal and background events to the data yields the single most-precise measurement of the top-quark mass, mtop = 172.85 ± 0.71 (stat) ± 0.85 (syst) GeV/c2.
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 Precision Measurements of the Top Quark Mass and Width with the D0 Detector by :
Download or read book Precision Measurements of the Top Quark Mass and Width with the D0 Detector written by and published by . This book was released on 2010 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since the discovery of the top quark in 1995 at the Fermliab Tevatron Collider, top quark properties have been measured with ever higher precision. In this article, recent measurements of the top quark mass and its width using up to 3.6 fb−1 of D0 data are summarized. Different techniques and final states have been examined and no deviations within these measurements have been observed. In addition to the direct measurements, a measurement of the top quark mass from its production cross section and a measurement of the top-antitop quark mass difference are discussed. With a mass of 173.3 ± 1.1 GeV, the top quark is the heaviest of all known fundamental particles. Due to the high mass, its Yukawa coupling is close to unity suggesting that it may play a special role in electroweak symmetry breaking. Precise measurements of both, the W boson and the top quark mass, constrain the mass of the yet unobserved Higgs boson and allow to restrict certain extensions of the Standard Model. At the Tevatron collider with a center-of-mass energy of 1.96 TeV, 85% of the top quark pairs are produced in quark-antiquark annihilation; 15% originate from gluon fusion. Top quarks are predicted to decay almost exclusively to a W boson and a bottom quark. According to the number of hadronic W decays, top events are classified into all-jets, lepton+jets and dilepton events. The lepton+jets channel is characterized by four jets, one isolated, energetic charged lepton and missing transverse energy. With 30%, the branching fraction of the lepton+jets channel is about seven times larger than the one of the dilepton channel whereas the signal to background ratio is about three times smaller. The main background in this final state comes from W +jets events. Instrumental background arises from events in which a jet is misidentified as an electron and events with heavy hadrons that decay into leptons which pass the isolation requirements. The topology of the dilepton channel is described by two jets, two isolated, energetic charged leptons and significant missing transverse energy from the undetected neutrinos. The main background are Z + jets and diboson events (WW/WZ/ZZ+jets) as well as instrumental background as characterized above. At the D0 experiment, different techniques are used to measure the top quark mass. They are summarized in the following sections together with the first measurement of the top anti-top quark mass difference and the first precise determination of the top quark width.
Book Synopsis Precision Measurement of the Top-quark Mass in Lepton+jets Final States by :
Download or read book Precision Measurement of the Top-quark Mass in Lepton+jets Final States written by and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We measure the mass of the top quark in lepton$+$jets final states using the full sample of $p\bar{p}$ collision data collected by the D0 experiment in Run II of the Fermilab Tevatron Collider at $\sqrt s=1.96 $TeV, corresponding to $9.7 {\rm fb}^{-1}$ of integrated luminosity. We use a matrix element technique that calculates the probabilities for each event to result from $t\bar t$ production or background. The overall jet energy scale is constrained in situ by the mass of the $W$ boson. We measure $m_t=174.98\pm0.76$ GeV. In conclusion, this constitutes the most precise single measurement of the top-quark mass.
Book Synopsis Precision Measurement of the Top Quark Mass in the Lepton + Jets Channel Using a Matrix Element Method with Quasi-Monte Carlo Integration by : Paul Joseph Lujan
Download or read book Precision Measurement of the Top Quark Mass in the Lepton + Jets Channel Using a Matrix Element Method with Quasi-Monte Carlo Integration written by Paul Joseph Lujan and published by . This book was released on 2009 with total page 314 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Precision Measurement of Top Quark Mass in Dilepton Channel by : Bodhitha Jayatilaka
Download or read book Precision Measurement of Top Quark Mass in Dilepton Channel written by Bodhitha Jayatilaka and published by . This book was released on 2006 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present recent measurements of the top quark mass using events collected at the CDF and D0 detectors from p{bar p} collisions at {radical}s = 1.96 TeV at the Fermilab Tevatron. These analyses are performed using events consistent with the decay channel t{bar t} {yields} {bar b}{ell}{sup -}{bar v}{sub {ell}}b{ell}' + v'{sub {ell}}, or the dilepton channel. 230-360 pb{sup -1} of data are used.
Book Synopsis Precision Measurement of the Mass of the Top Quark in Pp Collisions by : Carlos A. Garcia
Download or read book Precision Measurement of the Mass of the Top Quark in Pp Collisions written by Carlos A. Garcia and published by . This book was released on 2007 with total page 218 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Precision Measurement of the Top Quark Mass from Dilepton Events at CDF II. by :
Download or read book Precision Measurement of the Top Quark Mass from Dilepton Events at CDF II. written by and published by . This book was released on 2006 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Precision Measurement of the Top Quark Mass at CDF by : Michele Giunta
Download or read book Precision Measurement of the Top Quark Mass at CDF written by Michele Giunta and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Measurement of the Top Quark Mass in the Dilepton Final State Using the Matrix Element Method by : Alexander Grohsjean
Download or read book Measurement of the Top Quark Mass in the Dilepton Final State Using the Matrix Element Method written by Alexander Grohsjean and published by Springer Science & Business Media. This book was released on 2010-10-01 with total page 155 pages. Available in PDF, EPUB and Kindle. Book excerpt: The main pacemakers of scienti?c research are curiosity, ingenuity, and a pinch of persistence. Equipped with these characteristics a young researcher will be s- cessful in pushing scienti?c discoveries. And there is still a lot to discover and to understand. In the course of understanding the origin and structure of matter it is now known that all matter is made up of six types of quarks. Each of these carry a different mass. But neither are the particular mass values understood nor is it known why elementary particles carry mass at all. One could perhaps accept some small generic mass value for every quark, but nature has decided differently. Two quarks are extremely light, three more have a somewhat typical mass value, but one quark is extremely massive. It is the top quark, the heaviest quark and even the heaviest elementary particle that we know, carrying a mass as large as the mass of three iron nuclei. Even though there exists no explanation of why different particle types carry certain masses, the internal consistency of the currently best theory—the standard model of particle physics—yields a relation between the masses of the top quark, the so-called W boson, and the yet unobserved Higgs particle. Therefore, when one assumes validity of the model, it is even possible to take precise measurements of the top quark mass to predict the mass of the Higgs (and potentially other yet unobserved) particles.
Download or read book De Heylige Evangelien ... written by and published by . This book was released on 1692 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Precision Measurements of the Top Quark Mass in the Dileptonic Top Quark Pair Decay Channel at ATLAS by : Andreas Alexander Maier
Download or read book Precision Measurements of the Top Quark Mass in the Dileptonic Top Quark Pair Decay Channel at ATLAS written by Andreas Alexander Maier and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Precision Measurement of the Top Quark Mass in the Lepton + Jets Channel Using a Matrix Element Method with Quasi-Monte Carlo Integration by :
Download or read book Precision Measurement of the Top Quark Mass in the Lepton + Jets Channel Using a Matrix Element Method with Quasi-Monte Carlo Integration written by and published by . This book was released on 2009 with total page 177 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis presents a measurement of the top quark mass obtained from p{bar p} collisions at √s = 1.96 TeV at the Fermilab Tevatron using the CDF II detector. The measurement uses a matrix element integration method to calculate a t{bar t} likelihood, employing a Quasi-Monte Carlo integration, which enables us to take into account effects due to finite detector angular resolution and quark mass effects. We calculate a t{bar t} likelihood as a 2-D function of the top pole mass m{sub t} and [Delta]{sub JES}, where [Delta]{sub JES} parameterizes the uncertainty in our knowledge of the jet energy scale; it is a shift applied to all jet energies in units of the jet-dependent systematic error. By introducing [Delta]{sub JES} into the likelihood, we can use the information contained in W boson decays to constrain [Delta]{sub JES} and reduce error due to this uncertainty. We use a neural network discriminant to identify events likely to be background, and apply a cut on the peak value of individual event likelihoods to reduce the effect of badly reconstructed events. This measurement uses a total of 4.3 fb−1 of integrated luminosity, requiring events with a lepton, large E{sub T}, and exactly four high-energy jets in the pseudorapidity range.
Book Synopsis Precision Measurement of the Mass of the Top Quark in P Anti-p Collisions by :
Download or read book Precision Measurement of the Mass of the Top Quark in P Anti-p Collisions written by and published by . This book was released on 2007 with total page 125 pages. Available in PDF, EPUB and Kindle. Book excerpt: We report a measurement of the mass of the top quark (m{sub top}) in p{bar p} collisions at a center of mass energy of 1.96 TeV. The analysis is based on p{bar p}→t{bar t}→ lepton+jets data recorded with the D0 detector at the Fermilab Tevatron Collider. Events were preselected in the e+jets (913 events/pb of data) and in the [mu]+jets (871 events/pb of data) channels. These were analyzed through a comparison of the matrix element for the production and decay of the t{bar t} states with data, using a likelihood method and 'tagged' b quarks from the t → Wb decays.
Book Synopsis Precision Measurement of the Mass of the Top Quark in P $\bar{p}$ Collisions by :
Download or read book Precision Measurement of the Mass of the Top Quark in P $\bar{p}$ Collisions written by and published by . This book was released on 2007 with total page 125 pages. Available in PDF, EPUB and Kindle. Book excerpt: We report a measurement of the mass of the top quark (mtop) in p$ar{p}$ collisions at a center of mass energy of 1.96 TeV. The analysis is based on p$ar{p}$→t$ar{t}$→ lepton+jets data recorded with the D0 detector at the Fermilab Tevatron Collider. Events were preselected in the e+jets (913 events/pb of data) and in the ?+jets (871 events/pb of data) channels. These were analyzed through a comparison of the matrix element for the production and decay of the t$ar{t}$ states with data, using a likelihood method and 'tagged' b quarks from the t → Wb decays.
