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Measurements Of The Top Quark Mass With The D0 Detector
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Book Synopsis Measurements of the Top Quark Mass with the D0 Detector by :
Download or read book Measurements of the Top Quark Mass with the D0 Detector written by and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The mass of the top quark is a fundamental parameter of the standard model (SM) and has to be determined experimentally. In this talk, I present the most recent measurements of the top quark mass in $p\bar p$ collisions at $\sqrt s=1.96$~TeV recorded by the D0 experiment at the Fermilab Tevatron Collider. The measurements are performed in final states containing two leptons, using 5.4~\fb of integrated luminosity, and one lepton, using 9.7~\fb of integrated luminosity. The latter constitutes the most precise single measurement of the mass of the top quark, corresponding to a relative precision of 0.43\%. I conclude with a combination of our results with the results by the CDF collaboration, attaining a relative precision of 0.37\%.
Book Synopsis Measurements of the Top Quark Mass and Decay Width with the D0 Detector by :
Download or read book Measurements of the Top Quark Mass and Decay Width with the D0 Detector written by and published by . This book was released on 2011 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: The top quark discovery in 1995 at Fermilab is one of the major proofs of the standard model (SM). Due to its unique place in SM, the top quark is an important particle for testing the theory and probing for new physics. This article presents most recent measurements of top quark properties from the D0 detector. In particular, the measurement of the top quark mass, the top antitop mass difference and the top quark decay width. The discovery of the top quark in 1995 confirmed the existence of a third generation of quarks predicted in the standard model (SM). Being the heaviest elementary particle known, the top quark appears to become an important particle in our understanding of the standard model and physics beyond it. Because of its large mass the top quark has a very short lifetime, much shorter than the hadronization time. The predicted lifetime is only 3.3 · 10−25s. Top quark is the only quark whose properties can be studied in isolation. A Lorentz-invariant local Quantum Field Theory, the standard model is expected to conserve CP. Due to its unique properties, the top quark provides a perfect test of CPT invariance in the standard model. An ability to look at the quark before being hadronized allows to measure directly mass of the top quark and its antiquark. An observation of a mass difference between particle and antiparticle would indicate violation of CPT invariance. Top quark through its radiative loop correction to the W mass constrains the mass of the Higgs boson. A precise measurement of the top quark mass provides useful information to the search of Higgs boson by constraining its region of possible masses. Another interesting aspect is that the top quark's Yukawa coupling to the Higgs boson is very close to unity (0.996 ± 0.006). That implies it may play a special role in the electroweak symmetry breaking mechanism.
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 A Measurement of the Top Quark Mass with the D0 Detector at S**(1/2) by :
Download or read book A Measurement of the Top Quark Mass with the D0 Detector at S**(1/2) written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract Not Provided.
Book Synopsis Top Mass Measurements with the D0 Detector by :
Download or read book Top Mass Measurements with the D0 Detector written by and published by . This book was released on 2009 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: I present recent results related to the measurement of the top quark mass, using p{bar p} collisions recorded with the D0 Detector at the Tevatron. The results are: A direct measurement of the mass difference between top and anti-top quarks, Measurement of the top quark mass in the lepton+jets channel and in the dilepton channel.
Book Synopsis A Measurement of the Top Quark Mass with the D0 Detector at S**ư by :
Download or read book A Measurement of the Top Quark Mass with the D0 Detector at S**ư written by and published by . This book was released on 2004 with total page 123 pages. Available in PDF, EPUB and Kindle. Book excerpt: Using a data set of 158 and 169 pb−1 of D0 Run-II data in the electron and muon plus jets channel, respectively, the top quark mass has been measured using the Matrix Element Method. The method and its implementation are described. Its performance is studied in Monte Carlo using ensemble tests and the method is applied to the Moriond 2004 data set.
Download or read book Il credito fondiario written by and published by . This book was released on 1863 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Physics of the Top Quark at D0 New Measurement of the Production Cross Section and Mass by :
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 1997 with total page 20 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 √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−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} → bW {anti b}W− final states with one W decaying to q{anti q} and the other to e? or??. 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/c2. For this mass we measure the t{anti t} production cross section to be 5.5 ± 1.8 pb.
Book Synopsis Measurement of the Top Quark Mass at by :
Download or read book Measurement of the Top Quark Mass at written by and published by . This book was released on 1996 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt: The mass of the top quark is measured using a sample of 93 lepton + 4 or more jets events collected with the D0 detector at the FNAL Tevatron collider. The authors find the top quark mass is 169 ± 8(stat.) ± 8(syst.) GeV/c2. The analysis assumes that top quarks are produced as t{anti t} pairs that decay to W bosons and b quarks. The final states result when one W decays to e[nu] or [mu][nu] and the other W to q{anti q}. More than four jets may be present because of final and initial state radiation.
Book Synopsis Measurement of the Top Quark Mass and Kinematic Properties with the D0 Detector by :
Download or read book Measurement of the Top Quark Mass and Kinematic Properties with the D0 Detector written by and published by . This book was released on 1995 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Studies of the Top Quark with the D0 Detector by :
Download or read book Studies of the Top Quark with the D0 Detector written by and published by . This book was released on 1996 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: The observation of the top quark by the D0 experiment, at Fermilab's Tevatron proton-antiproton collider, is briefly reviewed. The analysis of the top quark mass in the lepton plus jets decay channels, resulting in m{sub t} (almost equal to) 200 GeV/c2 is reviewed; and a preliminary mass analysis from the dilepton decay channels resulting in m{sub t} = 145 " 25 (statistical) " 20 (systematic) GeV/c2 is presented. These mass measurements are compared with Standard Model limits from CERN's LEP experiments and the published CDF measurement. Preliminary observation of top quark-W boson correlation is shown.
Book Synopsis Measurement of the Mass of the Top Quark in Dilepton Final States with the D0 Detector by : Oleg Brandt
Download or read book Measurement of the Mass of the Top Quark in Dilepton Final States with the D0 Detector written by Oleg Brandt and published by . This book was released on 2006 with total page 118 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the Standard Model (SM) the top quark mass is a fundamental parameter. Its precise measurement is important to test the self-consistency of the SM. Additionally, it offers sensitivity to New Physics beyond the Standard Model. In proton anti-proton collisions at a centre-of-mass energy of {radical}s = 1.96 TeV t{bar t} quarks are pair-produced, each decaying into a W boson and a b quark. In the dilepton channel both W bosons decay leptonically. Because of the presence of two neutrinos in the final state the kinematics are underconstrained. A so-called Neutrino Weighting algorithm is used to calculate a weight for the consistency of a hypothesized top quark mass with the event kinematics. To render the problem solvable, the pseudorapidities of the neutrinos are assumed. The Maximum Method, which takes the maximum to the weight distribution as input to infer the top quark mass, is applied to approximately 370 pb{sup -1} of Run-II data, recorded by the D0 experiment at the Tevatron. The e{mu}-channel of the 835 pb{sup -1} dataset is analyzed.
Book Synopsis A Measurement of the Mass of the Top Quark Using the Ideogram Technique by :
Download or read book A Measurement of the Mass of the Top Quark Using the Ideogram Technique written by and published by . This book was released on 2009 with total page 130 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis describes a measurement of the mass of the top quark on data collected with the D0 detector at the Tevatron collider in the period from 2002 until 2006. The first chapter describes the Standard Model and the prominent role of the top quark mass. The second chapter gives a description of the D0 detector which is used for this measurement. After the p$\bar{p}$ collisions have been recorded, reconstruction of physics objects is required, which is described in Chapter 3. Chapter 4 describes how the interesting collisions in which top quarks are produced are separated from the `uninteresting' ones with a set of selection criteria. The method to extract the top quark mass from the sample of selected collisions (also called events), which is based on the ideogram technique, is explained in Chapter 5, followed in Chapter 6 by the description of the calibration of the method using simulation of our most precise knowledge of nature. Chapter 7 shows the result of the measurement together with some cross checks and an estimation of the uncertainty on this measurement. This thesis concludes with a constraint on the Higgs boson mass.
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.
Book Synopsis A Measurement of the Mass of the Top Quark in the Di-lepton Channels Using the D0 Detector at Fermilab by :
Download or read book A Measurement of the Mass of the Top Quark in the Di-lepton Channels Using the D0 Detector at Fermilab written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract Not Provided.
Book Synopsis Measurement of the Properties of the Top Quark at D{\O} by :
Download or read book Measurement of the Properties of the Top Quark at D{\O} written by and published by . This book was released on 2011 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: Different measurements of the properties of the top quark using up to 5.4 fb−1 collected with the D0 detector at the Fermilab Tevatron collider are presented. The top mass is obtained from a study of dilepton and lepton+jets final states, while the width is obtained from a combination of the measurements of the single top production via t-channel exchange and the determination of the t → Wb branching ratio. Furthermore the measurement of the helicity of the W boson from top quark decays, a measurement of t{bar t} spin correlations and a measurement of the jet pull (color flow) in t{bar t} events are presented. A wealth of measurements of properties of the top quark at D0 have been discussed showing the great performance of the Tevatron and the D0 detector. All results are consistent with the standard model expectations. The final D0 data sample will have 2-3 times the presented statistics allowing for new & more precise results in the future.
Book Synopsis Recent Results in the Top Quark Sector from the D0 Experiment by :
Download or read book Recent Results in the Top Quark Sector from the D0 Experiment written by and published by . This book was released on 2015 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: In these proceedings, I review recent measurements in the top quark sector in pp-bar collisions at a centre-of-mass energy of √s = 1.96 TeV in Run II of the Fermilab Tevatron Collider using the D0 detector. I will present the differential measurement of the tt-bar production cross section and the Tevatron combination of inclusive tt-bar cross section measurements; the first evidence of the production of single top quarks in the s-channel by D0 and the observation in combination with CDF. Furthermore, I will review the measurements of the forward-backward asymmetry in tt-bar events, and conclude with the world's most precise single measurement of the top quark mass, which is a fundamental parameter of the standard model, and present the Tevatron combination, which is the world's most precise determination of the top quark mass, with a relative precision of 0.37%.
