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Measurement Of The Running B Quark Mass Using E E Bbg Events
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Book Synopsis Measurement of the Running B-quark Mass Using Ee− 2!b{bar B}g Events by :
Download or read book Measurement of the Running B-quark Mass Using Ee− 2!b{bar B}g Events written by and published by . This book was released on 1999 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: We have studied the determination of the running b-quark mass, m{sub b}(M{sub Z}), using Z° decays into 3 or more hadronic jets. We calculated the ratio of e"3-jet fractions in ee− 2!b{bar b} vs. ee− 2!q{sub l}{bar q}{sub l} (q{sub l} = u or d or s) events at next-to-leading order in perturbative QCD using six different infra-red- and collinear-safe jet-finding algorithms. We compared with corresponding measurements from the SLD Collaboration and found a significant algorithm-dependence of the fitted m{sub b}(M{sub Z}) value. Our best estimate, taking correlations into account, is m{sub b}(M{sub Z}) = 2.52 ± 0.27(stat.){sub -0.47}{sup +0.33}(syst.){sub -1.46}{sup +0.54}(theor.) GeV/c2.
Book Synopsis Measurement of the Running B-quark Mass Using E+e- -> Bb̄g Events by : Arnd Brandenburg
Download or read book Measurement of the Running B-quark Mass Using E+e- -> Bb̄g Events written by Arnd Brandenburg and published by . This book was released on 1999 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Measurement of the Running B-quark Mass Using E[sup+]e[sup -][yields] B[bar B]g Events by :
Download or read book Measurement of the Running B-quark Mass Using E[sup+]e[sup -][yields] B[bar B]g Events written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We have studied the determination of the running b-quark mass, m[sub b](M[sub Z]), using Z[sup 0] decays into 3 or more hadronic jets. We calculated the ratio of[ge] 3-jet fractions in e[sup+]e[sup -][yields] b[bar b] vs. e[sup+]e[sup -][yields] q[sub l][bar q][sub l] (q[sub l]= u or d or s) events at next-to-leading order in perturbative QCD using six different infra-red- and collinear-safe jet-finding algorithms. We compared with corresponding measurements from the SLD Collaboration and found a significant algorithm-dependence of the fitted m[sub b](M[sub Z]) value. Our best estimate, taking correlations into account, is m[sub b](M[sub Z])= 2.52[+-] 0.27(stat.)[sub -0.47][sup+0.33](syst.)[sub -1.46][sup+0.54](theor.) GeV/c[sup 2].
Download or read book Physics Letters written by and published by . This book was released on 1999 with total page 792 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis First Measurement of the Running of the Top Quark Mass by : Matteo M. Defranchis
Download or read book First Measurement of the Running of the Top Quark Mass written by Matteo M. Defranchis and published by Springer Nature. This book was released on 2022-01-03 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this thesis, the first measurement of the running of the top quark mass is presented. This is a fundamental quantum effect that had never been studied before. Any deviation from the expected behaviour can be interpreted as a hint of the presence of physics beyond the Standard Model. All relevant aspects of the analysis are extensively described and documented. This thesis also describes a simultaneous measurement of the inclusive top quark-antiquark production cross section and the top quark mass in the simulation. The measured cross section is also used to precisely determine the values of the top quark mass and the strong coupling constant by comparing to state-of-the-art theoretical predictions. All the theoretical and experimental aspects relevant to the results presented in this thesis are discussed in the initial chapters in a concise but complete way, which makes the material accessible to a wider audience.
Book Synopsis Measurement of the Top Quark Mass from B-tagged Events in the Lepton Plus Jets Channel in Pp̄ Collisions at [square Root of S] by : Nathan Robert-Claire Eddy
Download or read book Measurement of the Top Quark Mass from B-tagged Events in the Lepton Plus Jets Channel in Pp̄ Collisions at [square Root of S] written by Nathan Robert-Claire Eddy and published by . This book was released on 1999 with total page 262 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis A Measurement of the Mass of the Top Quark in Lepton + Jets Events at CDF by : Erik Matthews Brubaker
Download or read book A Measurement of the Mass of the Top Quark in Lepton + Jets Events at CDF written by Erik Matthews Brubaker and published by . This book was released on 2004 with total page 236 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Measurement of the Top Quark Mass at D0 Run II with the Matrix Element Method in the Lepton+Jets Final State by : Philipp Schieferdecker
Download or read book Measurement of the Top Quark Mass at D0 Run II with the Matrix Element Method in the Lepton+Jets Final State written by Philipp Schieferdecker and published by . This book was released on 2005 with total page 182 pages. Available in PDF, EPUB and Kindle. Book excerpt: The mass of the top quark is a fundamental parameter of the Standard Model. Its precise knowledge yields valuable insights into unresolved phenomena in and beyond the Standard Model. A measurement of the top quark mass with the matrix element method in the lepton+jets final state in D0 Run II is presented. Events are selected requiring an isolated energetic charged lepton (electron or muon), significant missing transverse energy, and exactly four calorimeter jets. For each event, the probabilities to originate from the signal and background processes are calculated based on the measured kinematics, the object resolutions and the respective matrix elements. The jet energy scale is known to be the dominant source of systematic uncertainty. The reference scale for the mass measurement is derived from Monte Carlo events. The matrix element likelihood is defined as a function of both, m{sub top} and jet energy scale JES, where the latter represents a scale factor with respect to the reference scale. The top mass is obtained from a two-dimensional correlated fit, and the likelihood yields both the statistical and jet energy scale uncertainty. Using a dataset of 320 pb{sup -1} of D0 Run II data, the mass of the top quark is measured to be: m{sub top}{sup {ell}+jets} = 169.5 {+-} 4.4(stat. + JES){sub -1.6}{sup +1.7}(syst.) GeV; m{sub top}{sup e+jets} = 168.8 {+-} 6.0(stat. + JES){sub -1.9}{sup +1.9}(syst.) GeV; m{sub top}{sup {mu}+jets} = 172.3 {+-} 9.6(stat.+JES){sub -3.3}{sup +3.4}(syst.) GeV. The jet energy scale measurement in the {ell}+jets sample yields JES = 1.034 {+-} 0.034, suggesting good consistency of the data with the simulation. The measurement forecasts significant improvements to the total top mass uncertainty during Run II before the startup of the LHC, as the data sample will grow by a factor of ten and D0's tracking capabilities will be employed in jet energy reconstruction and flavor identification.
Book Synopsis Proceedings Of The 29th International Conference On High Energy Physics: Ichep '98 (In 2 Volumes) by : Alan Astbury
Download or read book Proceedings Of The 29th International Conference On High Energy Physics: Ichep '98 (In 2 Volumes) written by Alan Astbury and published by World Scientific. This book was released on 1999-06-11 with total page 1899 pages. Available in PDF, EPUB and Kindle. Book excerpt: These proceedings consist of plenary rapporteur talks covering topics of major interest to the high energy physics community and parallel sessions papers which describe recent research results and future plans.
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 in the Dilepton Final State Using the Matrix Element Method by :
Download or read book Measurement of the Top Quark Mass in the Dilepton Final State Using the Matrix Element Method written by and published by . This book was released on 2008 with total page 153 pages. Available in PDF, EPUB and Kindle. Book excerpt: The top quark, discovered in 1995 by the CDF and D0 experiments at the Fermilab Tevatron Collider, is the heaviest known fundamental particle. The precise knowledge of its mass yields important constraints on the mass of the yet-unobserved Higgs boson and allows to probe for physics beyond the Standard Model. The first measurement of the top quark mass in the dilepton channel with the Matrix Element method at the D0 experiment is presented. After a short description of the experimental environment and the reconstruction chain from hits in the detector to physical objects, a detailed review of the Matrix Element method is given. The Matrix Element method is based on the likelihood to observe a given event under the assumption of the quantity to be measured, e.g. the mass of the top quark. The method has undergone significant modifications and improvements compared to previous measurements in the lepton+jets channel: the two undetected neutrinos require a new reconstruction scheme for the four-momenta of the final state particles, the small event sample demands the modeling of additional jets in the signal likelihood, and a new likelihood is designed to account for the main source of background containing tauonic Z decay. The Matrix Element method is validated on Monte Carlo simulated events at the generator level. For the measurement, calibration curves are derived from events that are run through the full D0 detector simulation. The analysis makes use of the Run II data set recorded between April 2002 and May 2008 corresponding to an integrated luminosity of 2.8 fb−1. A total of 107 t{bar t} candidate events with one electron and one muon in the final state are selected. Applying the Matrix Element method to this data set, the top quark mass is measured to be m{sub top}{sup Run IIa} = 170.6 ± 6.1(stat.){sub -1.5}{sup +2.1}(syst.)GeV; m{sub top}{sup Run IIb} = 174.1 ± 4.4(stat.){sub -1.8}{sup +2.5}(syst.)GeV; m{sub top}{sup comb} = 172.9 ± 3.6(stat.) ± 2.3(syst.)GeV. Systematic uncertainties are discussed, and the results are interpreted within the Standard Model of particle physics. As the main systematic uncertainty on the top quark mass comes from the knowledge of the absolute jet energy scale, studies for a simultaneous measurement of the top quark mass and the b jet energy scale are presented. The prospects that such a simultaneous determination offer for future measurements of the top quark mass are outlined.
Book Synopsis A Precise Measurement of the Top Quark Mass by :
Download or read book A Precise Measurement of the Top Quark Mass written by and published by . This book was released on 2007 with total page 246 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present a measurement of the mass of the top quark using data from proton-antiproton collisions recorded at the CDF experiment in Run II of the Fermilab Tevatron. Events are selected from the single lepton plus jets final state (t$\bar{t}$ → W+bW-$\bar{b}$ → lvbq$\bar{q}$'$\bar{b}$). The top quark mass is extracted using a calculation of the probability density for a t$\bar{t}$ final state to resemble a data event. This probability density is a function of both top quark mass and energy scale of calorimeter jets, constrained in situ with the hadronic W boson mass. Using 167 events observed in 955 pb-1 integrated luminosity, we achieve the single most precise measurement of top quark mass to date of 170.8 ± 2.2 (stat.) ± 1.4 (syst.) GeV/c2, where the quoted statistical uncertainty includes uncertainty from the determination of the jet energy scale.
Book Synopsis Measurement of the Top Quark Mass Using Dilepton Events and a Neutrino Weighting Algorithm with the DØ Experiment at the Tevatron (Run II) by : Jörg Meyer
Download or read book Measurement of the Top Quark Mass Using Dilepton Events and a Neutrino Weighting Algorithm with the DØ Experiment at the Tevatron (Run II) written by Jörg Meyer and published by . This book was released on 2007 with total page 110 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Measurement of the Top Quark Mass Using Dilepton Events and a Neutrino Weighting Algorithm with the D0 Experiment at the Tevatron (Run II). by :
Download or read book Measurement of the Top Quark Mass Using Dilepton Events and a Neutrino Weighting Algorithm with the D0 Experiment at the Tevatron (Run II). written by and published by . This book was released on 2007 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt: Elementary particle physics raises questions that are several thousand years old. What are the fundamental components of matter and how do they interact? These questions are linked to the question of what happened in the very first moments after the creation of the universe. Modern physics systematically tests nature to find answers to these and other fundamental questions. Precise theories are developed that describe various phenomena and at the same time are reduced to a few basic principals of nature. Simplification and reduction have always been guiding concepts of physics. The interplay between experimental data and theoretical descriptions led to the Standard Model of elementary particle physics. It summarizes the laws of nature and is one of most precise descriptions of nature achieved by mankind. Despite the great success of the Standard Model it is not the ultimate theory of everything. Models beyond the Standard Model try to unify all interactions in one grand unified theory. The number of free parameters is attempted to be reduced. Gravity is attempted to be incorporated. Extensions to the Standard Model like supersymmetry address the so-called hierarchy problem. Precision measurements are the key for searches of new particles and new physics. A powerful tool of experimental particle physics are particle accelerators. They provide tests of the Standard Model at smallest scales. New particles are produced and their properties are investigated. In 1995 the heaviest known elementary particle, called top quark, has been discovered at Fermilab. It differs from all other lighter quarks due to the high mass and very short lifetime. This makes the top quark special and an interesting object to be studied. A rich program of top physics at Fermilab investigates whether the top quark is really the particle as described by the Standard Model. The top quark mass is a free parameter of the theory that has been measured precisely. This thesis presents a precise measurement of the top quark mass by the D0 experiment at Fermilab in the dilepton final states. The comparison of the measured top quark masses in different final states allows an important consistency check of the Standard Model. Inconsistent results would be a clear hint of a misinterpretation of the analyzed data set. With the exception of the Higgs boson, all particles predicted by the Standard Model have been found. The search for the Higgs boson is one of the main focuses in high energy physics. The theory section will discuss the close relationship between the physics of the Higgs boson and the top quark.
Book Synopsis Measurement of the Top Quark Mass in the Di-lepton Channel Using the Dalitz-Goldstein Method by :
Download or read book Measurement of the Top Quark Mass in the Di-lepton Channel Using the Dalitz-Goldstein Method written by and published by . This book was released on 2010 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation describes a measurement of the mass of the top quark using a method developed by G. Goldstein and R.H. Dalitz. It is based on 2.0 fb−1 of data collected by the Collider Detector Facility at Fermi National Accelerator Laboratories. Di-lepton events were observed from colliding protons with anti-protons with √s = 1.96 TeV in the Tevatron Collider. A total of 145 candidate events were observed with 49 expected to be from background. These events include two neutrinos which elude detection. The method begins by assuming an initial top quark mass and solves for the neutrino momenta using a geometrical construction. The method samples over a range of likely top quark masses choosing the most consistent mass via a likelihood function. An important distinguishing feature of this method from others is its lack of dependence on the missing transverse energy, a quantity that is poorly measured by the experiment. This analysis determines the top quark mass to be M{sub top} = 172.3 ± 3.4(stat.) ± 2.0(syst.) GeV/c2 (M{sub top} = 170.5 ± 3.7(stat.) ± 1.8(syst.) GeV/c2 with b-tagging).
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.
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