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Measurement Of The Top Quark Mass Using Template Methods On Dilepton Events In P Anti P Collisions At S1 2
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Book Synopsis Measurement of the Top Quark Mass Using Template Methods on Dilepton Events in P Anti-p Collisions at S**1/2 by :
Download or read book Measurement of the Top Quark Mass Using Template Methods on Dilepton Events in P Anti-p Collisions at S**1/2 written by and published by . This book was released on 2006 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt: The authors describe a measurement of the top quark mass from events produced in p{bar p} collisions at a center-of-mass energy of 1.96 TeV, using the Collider Detector at Fermilab. They identify t{bar t} candidates where both W bosons from the top quarks decay into leptons (e[nu], [mu][nu], or [tau][nu]) from a data sample of 360 pb−1. The top quark mass is reconstructed in each event separately by three different methods, which draw upon simulated distributions of the neutrino pseudorapidity, t{bar t} longitudinal momentum, or neutrino azimuthal angle in order to extract probability distributions for the top quark mass. For each method, representative mass distributions, or templates, are constructed from simulated samples of signal and background events, and parameterized to form continuous probability density functions. A likelihood fit incorporating these parameterized templates is then performed on the data sample masses in order to derive a final top quark mass. Combining the three template methods, taking into account correlations in their statistical and systematic uncertainties, results in a top quark mass measurement of 170.1 ± 6.0(stat.) ± 4.1(syst.) GeV/c2.
Book Synopsis Measurement of the Top Quark Mass Using Template Methods on Dilepton Events in P Anti-p Collisions at S**ư by :
Download or read book Measurement of the Top Quark Mass Using Template Methods on Dilepton Events in P Anti-p Collisions at S**ư written by and published by . This book was released on 2006 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt: The authors describe a measurement of the top quark mass from events produced in p{bar p} collisions at a center-of-mass energy of 1.96 TeV, using the Collider Detector at Fermilab. They identify t{bar t} candidates where both W bosons from the top quarks decay into leptons (e?,??, or??) from a data sample of 360 pb−1. The top quark mass is reconstructed in each event separately by three different methods, which draw upon simulated distributions of the neutrino pseudorapidity, t{bar t} longitudinal momentum, or neutrino azimuthal angle in order to extract probability distributions for the top quark mass. For each method, representative mass distributions, or templates, are constructed from simulated samples of signal and background events, and parameterized to form continuous probability density functions. A likelihood fit incorporating these parameterized templates is then performed on the data sample masses in order to derive a final top quark mass. Combining the three template methods, taking into account correlations in their statistical and systematic uncertainties, results in a top quark mass measurement of 170.1 ± 6.0(stat.) ± 4.1(syst.) GeV/c2.
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 Measurement of the T Anti-t Production Cross Section and Top Quark Mass Extraction Using Dilepton Events in P Anti-p Collisions by :
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.
Book Synopsis Top Quark Mass Measurement Using the Template Method at CDF. by :
Download or read book Top Quark Mass Measurement Using the Template Method at CDF. written by and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We present a measurement of the top quark mass in the lepton+jets and dilepton channels of t{bar t} decays using the template method. The data sample corresponds to an integrated luminosity of 5.6 fb−1 of p{bar p} collisions at Tevatron with √s = 1.96 TeV, collected with the CDF II detector. The measurement is performed by constructing templates of three kinematic variables in the lepton+jets and two kinematic variables in the dilepton channel. The variables are two reconstructed top quark masses from different jets-to-quarks combinations and the invariant mass of two jets from the W decay in the lepton+jets channel, and a reconstructed top quark mass and m{sub T2}, a variable related to the transverse mass in events with two missing particles, in the dilepton channel. The simultaneous fit of the templates from signal and background events in the lepton+jets and dilepton channels to the data yields a measured top quark mass of M{sub top} = 172.1 ± 1.1 (stat) ± 0.9 (syst) GeV/c2.
Book Synopsis Top Quark Mass Measurement from Dilepton Events at CDF II with the Matrix-element Method by :
Download or read book Top Quark Mass Measurement from Dilepton Events at CDF II with the Matrix-element Method written by and published by . This book was released on 2006 with total page 21 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Measurement of the Top Quark Mass in P Anti-p Collisions at S**1/2 by :
Download or read book Measurement of the Top Quark Mass in P Anti-p Collisions at S**1/2 written by and published by . This book was released on 2006 with total page 23 pages. Available in PDF, EPUB and Kindle. Book excerpt: We report the first measurement of the top quark mass using the decay length technique in p{bar p} collisions at a center-of-mass energy of 1.96 TeV. This technique uses the measured flight distance of the b hadron to infer the mass of the top quark in lepton plus jets events with missing transverse energy. It relies solely on tracking and avoids the jet energy scale uncertainty that is common to all other methods used so far. We apply our novel method to a 695 pb−1 data sample recorded by the CDF II detector at Fermilab and extract a measurement of m{sub t} = 180.7{sub -13.4}{sup +15.5}(stat.) ± 8.6 (syst.) GeV/c2. While the uncertainty of this result is larger than that of other measurements, the dominant uncertainties in the decay length technique are uncorrelated with those in other methods. This result can help reduce the overall uncertainty when combined with other existing measurements of the top quark mass.
Book Synopsis Measurement of the Top Quark Mass Using the Template Method in the Lepton Plus Jets Channel with in Situ W ---] J J Calibration at CDF-II. by : T. Maruyama
Download or read book Measurement of the Top Quark Mass Using the Template Method in the Lepton Plus Jets Channel with in Situ W ---] J J Calibration at CDF-II. written by T. Maruyama and published by . This book was released on 2006 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt: We report an updated measurement of the top quark mass in the lepton plus jets channel of t{bar t} events from p{bar p} collisions at {radical}s = 1.96 TeV. This measurement uses a dataset with integrated luminosity of 680 pb{sup -1}, containing 360 t{bar t} candidates separated into four subsamples. A top quark mass is reconstructed for each event by using energy and momentum constraints on the top quark pair decay products. We also employ the reconstructed mass of hadronic W boson decays W {yields} jj to constrain in situ the largest systematic uncertainty of the top quark mass measurement: the jet energy scale. Monte Carlo templates of the reconstructed top quark and W boson mass are produced as a function of the true top quark mass and the jet energy scale. The distribution of reconstructed top quark and W boson mass in the data are compared to the Monte Carlo templates using a likelihood fit to obtain: M{sub top} = 173.4 {+-} 2.8 GeV/c{sup 2}.
Book Synopsis A Precise Measurement of the Top Quark Mass in Dilepton Final States Using 9.7 Fb$^{-1}$ of D{\O} Run II Data by :
Download or read book A Precise Measurement of the Top Quark Mass in Dilepton Final States Using 9.7 Fb$^{-1}$ of D{\O} Run II Data written by and published by . This book was released on 2015 with total page 214 pages. Available in PDF, EPUB and Kindle. Book excerpt: The top quark is a very special fundamental particle in the Standard Model (SM) mainly due to its heavy mass. The top quark has extremely short lifetime and decays before hadronization. This reduces the complexity for the measurement of its mass. The top quark couples very strongly to the Higgs boson since the fermion-Higgs Yukawa coupling linearly depends on the fermion's mass. Therefore, the top quark is also heavily involved in Higgs production and related study. A precise measurement of the top quark mass is very important, as it allows for self-consistency check of the SM, and also gives a insight about the stability of our universe in the SM context. This dissertation presents my work on the measurement of the top quark mass in dilepton final states of t$\bar{t}$ events in p$\bar{p}$ collisions at √s = 1.96 TeV, using the full DØ Run II data corresponding to an integrated luminosity of 9.7 fb-1 at the Fermilab Tevatron. I extracted the top quark mass by reconstructing event kinematics, and integrating over expected neutrino rapidity distributions to obtain solutions over a scanned range of top quark mass hypotheses. The analysis features a comprehensive optimization that I made to minimize the expected statistical uncertainty. I also improve the calibration of jets in dilepton events by using the calibration determined in t$\bar{t}$ → lepton+jets events, which reduces the otherwise limiting systematic uncertainty from the jet energy scale. The measured mass is 173.11 ± 1.34(stat)+0.83 -0.72(sys) GeV .
Book Synopsis Measurement of the Top Quark Mass in P Anti-p Collisions at S**ư by :
Download or read book Measurement of the Top Quark Mass in P Anti-p Collisions at S**ư written by and published by . This book was released on 2006 with total page 23 pages. Available in PDF, EPUB and Kindle. Book excerpt: We report the first measurement of the top quark mass using the decay length technique in p{bar p} collisions at a center-of-mass energy of 1.96 TeV. This technique uses the measured flight distance of the b hadron to infer the mass of the top quark in lepton plus jets events with missing transverse energy. It relies solely on tracking and avoids the jet energy scale uncertainty that is common to all other methods used so far. We apply our novel method to a 695 pb−1 data sample recorded by the CDF II detector at Fermilab and extract a measurement of m{sub t} = 180.7{sub -13.4}{sup +15.5}(stat.) ± 8.6 (syst.) GeV/c2. While the uncertainty of this result is larger than that of other measurements, the dominant uncertainties in the decay length technique are uncorrelated with those in other methods. This result can help reduce the overall uncertainty when combined with other existing measurements of the top quark mass.
Book Synopsis Measurement of the Top Quark Mass with the Dynamical Likelihood Method Using Lepton Plus Jets Events with B-tags in P Anti-p Collisions at S**1/2 by :
Download or read book Measurement of the Top Quark Mass with the Dynamical Likelihood Method Using Lepton Plus Jets Events with B-tags in P Anti-p Collisions at S**1/2 written by and published by . This book was released on 2005 with total page 66 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report describes a measurement of the top quark mass, M{sub top}, with the dynamical likelihood method (DLM) using the CDF II detector at the Fermilab Tevatron. The Tevatron produces top/anti-top (t{bar t}) pairs in p{bar p} collisions at a center-of-mass energy of 1.96 TeV. The data sample used in this analysis was accumulated from March 2002 through August 2004, which corresponds to an integrated luminosity of 318 pb−1. They use the t{bar t} candidates in the ''lepton+jets'' decay channel, requiring at least one jet identified as a b quark by finding an displaced secondary vertex. The DLM defines a likelihood for each event based on the differential cross section as a function of M{sub top} per unit phase space volume of the final partons, multiplied by the transfer functions from jet to parton energies. The method takes into account all possible jet combinations in an event, and the likelihood is multiplied event by event to derive the top quark mass by the maximum likelihood method. Using 63 t{bar t} candidates observed in the data, with 9.2 events expected from background, they measure the top quark mass to be 173.2{sub -2.4}{sup +2.6}(stat.) ± 3.2(syst.) GeV/c2, or 173.2{sub -4.0}{sup +4.1} GeV/c2.
Book Synopsis Measurement of the Top Quark Mass in Dilepton Final States with the Neutrino Weighting Method by :
Download or read book Measurement of the Top Quark Mass in Dilepton Final States with the Neutrino Weighting Method written by and published by . This book was released on 2012 with total page 224 pages. Available in PDF, EPUB and Kindle. Book excerpt: The top quark is the heaviest fundamental particle observed to date. The mass of the top quark is a free parameter in the Standard Model (SM). A precise measurement of its mass is particularly important as it sets an indirect constraint on the mass of the Higgs boson. It is also a useful constraint on contributions from physics beyond the SM and may play a fundamental role in the electroweak symmetry breaking mechanism. I present a measurement of the top quark mass in the dilepton channel using the Neutrino Weighting Method. The data sample corresponds to an integrated luminosity of 4.3 fb-1 of p$\bar{p}$ collisions at Tevatron with √s = 1.96 TeV, collected with the DØ detector. Kinematically under-constrained dilepton events are analyzed by integrating over neutrino rapidity. Weight distributions of t$\bar{t}$ signal and background are produced as a function of the top quark mass for different top quark mass hypotheses. The measurement is performed by constructing templates from the moments of the weight distributions and input top quark mass, followed by a subsequent likelihood t to data. The dominant systematic uncertainties from jet energy calibration is reduced by using a correction from `+jets channel. To replicate the quark avor dependence of the jet response in data, jets in the simulated events are additionally corrected. The result is combined with our preceding measurement on 1 fb-1 and yields mt = 174.0± 2.4 (stat.) ±1.4 (syst.) GeV.
Book Synopsis Measurement of the Top Quark Mass in $p \bar{p}$ Collisions Using Events with Two Leptons by :
Download or read book Measurement of the Top Quark Mass in $p \bar{p}$ Collisions Using Events with Two Leptons written by and published by . This book was released on 2012 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present a measurement of the top quark mass (m{sub t}) in p{bar p} collisions at √s = 1.96 TeV using t{bar t} events with two leptons (ee, e? or??) in the final state in 4.3 fb−1 of data collected with the D0 detector at the Fermilab Tevatron collider. We analyze the kinematically underconstrained dilepton events by integrating over the neutrino rapidity distributions. We reduce the dominant systematic uncertainties from jet energy calibration using a correction obtained from t{bar t} → l + jets events. We also correct jets in simulated events to replicate the quark flavor dependence of the jet response in data. In combination with our previous analysis, we measure m{sub t} = 174.0 ± 2.4(stat) ± 1.4(syst) GeV.
Book Synopsis Measurement of the Top Quark Mass with the Dynamical Likelihood Method Using Lepton Plus Jets Events with B-tags in P Anti-p Collisions at S**ư by :
Download or read book Measurement of the Top Quark Mass with the Dynamical Likelihood Method Using Lepton Plus Jets Events with B-tags in P Anti-p Collisions at S**ư written by and published by . This book was released on 2005 with total page 66 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report describes a measurement of the top quark mass, M{sub top}, with the dynamical likelihood method (DLM) using the CDF II detector at the Fermilab Tevatron. The Tevatron produces top/anti-top (t{bar t}) pairs in p{bar p} collisions at a center-of-mass energy of 1.96 TeV. The data sample used in this analysis was accumulated from March 2002 through August 2004, which corresponds to an integrated luminosity of 318 pb−1. They use the t{bar t} candidates in the ''lepton+jets'' decay channel, requiring at least one jet identified as a b quark by finding an displaced secondary vertex. The DLM defines a likelihood for each event based on the differential cross section as a function of M{sub top} per unit phase space volume of the final partons, multiplied by the transfer functions from jet to parton energies. The method takes into account all possible jet combinations in an event, and the likelihood is multiplied event by event to derive the top quark mass by the maximum likelihood method. Using 63 t{bar t} candidates observed in the data, with 9.2 events expected from background, they measure the top quark mass to be 173.2{sub -2.4}{sup +2.6}(stat.) ± 3.2(syst.) GeV/c2, or 173.2{sub -4.0}{sup +4.1} GeV/c2.
Book Synopsis The First Measurement of the Top Quark Mass at CDF II in the Lepton+jets and Dilepton Channels Simultaneously by :
Download or read book The First Measurement of the Top Quark Mass at CDF II in the Lepton+jets and Dilepton Channels Simultaneously written by and published by . This book was released on 2008 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: The authors present a measurement of the mass of the top quark using data corresponding to an integrated luminosity of 1.9 fb−1 of p{bar p} collisions collected at (square root)s = 1.96 TeV with the CDF II detector at Fermilab's Tevatron. This is the first measurement of the top quark mass using top-antitop pair candidate events in the lepton + jets and dilepton decay channels simultaneously. They reconstruct two observables in each channel and use a non-parametric kernel density estimation technique to derive two-dimensional probability density functions from simulated signal and background samples. The observables are the top quark mass and the invariant mass of two jets from the W decay in the lepton + jets channel, and the top quark mass and the scalar sum of transverse energy of the event in the diletpon channel. They perform a simultaneous fit for the top quark mass and the jet energy scale, which is constrained in situ by the hadronic W boson mass. using 332 lepton + jets candidate events and 144 diletpon candidate events, they measure the top quark mass to be m{sub top} = 171.9 ± 1.7 (stat. + JES) ± 1.1 (other sys.) GeV/c2 = 171.9 ± 2.0 GeV/c2.
Book Synopsis Measurement of the Top Quark Mass by :
Download or read book Measurement of the Top Quark Mass written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation describes the measurement of the top quark mass m[sub t] using events recorded during a 125 pb[sup -1] exposure of the D0 detector to[radical]s=1.8 TeV[anti p]p collisions. Six events consistent with the hypothesis t[anti t][yields] bW[sup+], [anti b]W[sup -][yields] b[anti l][nu], [anti b]l[anti[nu]] form the dilepton sample. The kinematics of such events may be reconstructed for any assumed mt, and the likelihood of each such solution evaluated. A measurement of m[sub t] based on these relative solution likelihoods gives m[sub t]= 169.9[+-] 14.8 (stat.)[+-] 3. 8 (syst.) GeV/c[sup 2]. A 2C kinematic fit is performed on a sample of 77 events consistent with t[anti t][yields] bW[sup+], [anti b]W[sup -][yields] b[anti l][nu], [anti b]q[anti q], and this, in combination with an estimate on the likelihood that each event is top, yields m[sub t]= 173.3[+-] 5.6 (stat.)[+-] 6.2 (syst.) GeV/c[sup 2] . A combination of these two measurements gives m[sub t]= 173.1[+-] 5.2 (stat.)[+-] 5.7 (syst.) GeV/c[sup 2].
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.
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