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ISBN 13 :
Total Pages : 11 pages
Book Rating : 4.:/5 (925 download)
Download or read book Measurement of the Top-Quark Mass in the ${t\bar{t}}$ Dilepton Channel Using the Full CDF Run II Data Set written by and published by . This book was released on 2015 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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ISBN 13 :
Total Pages : 153 pages
Book Rating : 4.:/5 (727 download)
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.
Author : Tuula Maki
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ISBN 13 :
Total Pages : 3 pages
Book Rating : 4.:/5 (316 download)
Download or read book Measurement of the Top Quark Mass in the Dilepton Channel at CDF and written by Tuula Maki and published by . This book was released on 2005 with total page 3 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present recent analyses of the top quark mass measurement in dileptonic channel. The measurements use 200-360 pb{sup -1} of data collected by CDF and D0 experiments. The future prospects are discussed as well.
Author : Bodhitha Anjalike Jayatilaka
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ISBN 13 :
Total Pages : 272 pages
Book Rating : 4.3/5 (91 download)
Download or read book A Measurement of the Top Quark Mass in the Dilepton Decay Channel at CDF II. written by Bodhitha Anjalike Jayatilaka and published by . This book was released on 2006 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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ISBN 13 :
Total Pages : 24 pages
Book Rating : 4.:/5 (727 download)
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.
Author : Simon Sabik
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ISBN 13 : 9780494159248
Total Pages : 218 pages
Book Rating : 4.1/5 (592 download)
Download or read book Measurement of the Top Quark Mass in the Dilepton Channel Using the Neutrino Weighting Algorithm at CDF II. written by Simon Sabik and published by . This book was released on 2006 with total page 218 pages. Available in PDF, EPUB and Kindle. Book excerpt: We measure the top quark mass using approximately 359 pb-1 of data from pp− collisions at s = 1.96 GeV at CDF Run II. We select tt− candidates that are consistent with two W bosons decaying to a charged lepton and a neutrino following tt− & rarr; W+W-bb− & rarr; l+l- nn & d1; bb−. Only one of the two charged leptons is required to be identified as an electron or a muon candidate, while the other is simply a well measured track. We use a neutrino weighting algorithm which weighs each possibility of neutrino direction to reconstruct a top quark mass in each event. We compare the resulting distribution to Monte Carlo templates to obtain a top quark mass of 170.8+6.9-6.5 (stat) +/- 4.6 (syst) GeV/c 2.
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ISBN 13 :
Total Pages : 6 pages
Book Rating : 4.:/5 (925 download)
Download or read book Top Quark Physics at the Tevatron written by and published by . This book was released on 2015 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: An overview of recent top quark measurements using the full Run II data set of CDF or D0 at the Tevatron is presented. Results are complementary to the ones at the LHC. Recent measurements of the production cross section of top quarks in strong and electroweak production and of top quark production asymmetries are presented. The latter includes the measurement of the tt-bar production asymmetry by D0 in the dilepton decay channel. Within their uncertainties the results from all these measurements agree with their respective Standard Model expectation. Finally latest updates on measurements of the top quark mass are discussed, which at the time of the conference are the most precise determinations.
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ISBN 13 :
Total Pages : 21 pages
Book Rating : 4.:/5 (873 download)
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:
Author : Oleg Brandt
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ISBN 13 :
Total Pages : 118 pages
Book Rating : 4.:/5 (316 download)
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.
Author : Bodhitha Jayatilaka
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ISBN 13 :
Total Pages : 9 pages
Book Rating : 4.:/5 (316 download)
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.
Author : Teresa Spreitzer
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ISBN 13 : 9780494713709
Total Pages : 282 pages
Book Rating : 4.7/5 (137 download)
Download or read book Measurement of the Top Quark Pair Production Cross-Section in the Dilepton Channel Using Lepton Plus Track Selection and Identified B-jets written by Teresa Spreitzer and published by . This book was released on 2008 with total page 282 pages. Available in PDF, EPUB and Kindle. Book excerpt: Using 1.0 fb-1 of data collected by the Collider Detector at Fermilab (CDF) from Run II of the Fermilab Tevatron, we measure the tt ̄ production cross-section in events with two leptons, significant missing transverse energy, and ≥ 2 jets, at least one of which is identified as a b-jet. As the Run II dataset grows, more stringent tests of Standard Model predictions for the top quark sector are becoming possible. The dilepton channel, where both top quarks decay t → Wb → ℓvb, is of particular interest due to its high purity. Use of an isolated Crack as the second lepton significantly increases the dilepton acceptance, at the price of some increase in background, particularly from W + jets events where one of the jets is identified as a lepton. To control the increase in background we add to the event selection the requirement that at least one of the jets be identified as a b-jet, reducing the background contribution from all sources. Assuming a branching ratio of BR(W → ℓ v) = 10.8 % and a top mass of mt = 175 GeV/c2 , the measured cross-section is sigma(pp → tt) = 10.5 +/- 1.8 (stat.) +/- 0.8 (syst. ) +/- 0.6 (lumi.) pb.
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ISBN 13 :
Total Pages : 7 pages
Book Rating : 4.:/5 (727 download)
Download or read book Measurement of the Top Quark Mass in the Dilepton Channel written by and published by . This book was released on 2006 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present a measurement of the top quark mass in the dilepton channel based on approximately 370 pb−1 of data collected by the D0 experiment during Run II of the Fermilab Tevatron collider. We employ two different methods to extract the top quark mass. We show that both methods yield consistent results using ensemble tests of events generated with the D0 Monte Carlo simulation. We combine the results from the two methods to obtain a top quark mass m{sub t} = 178.1 ± 8.2 GeV. The statistical uncertainty is 6.7 GeV and the systematic uncertainty is 4.8 GeV.
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ISBN 13 :
Total Pages : 180 pages
Book Rating : 4.:/5 (727 download)
Download or read book Measurement of the Top Quark Mass Simultaneously in Dilepton and Lepton + Jets Decay Channels written by and published by . This book was released on 2008 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt: The authors present the first measurement of the top quark mass using simultaneously data from two decay channels. They use a data sample of (square root)s = 1.96 TeV collisions with integrated luminosity of 1.9 fb−1 collected by the CDF II detector. They select dilepton and lepton + jets channel decays of t{bar t} pairs and reconstruct two observables in each topology. They use non-parametric techniques to derive probability density functions from simulated signal and background samples. The observables are the reconstructed top quark mass and the scalar sum of transverse energy of the event in the dilepton topology and the reconstructed top quark mass and the invariant mass of jets from the W boson decay in lepton + jets 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 resonance from the lepton + jets channel. Using 144 dilepton candidate events and 332 lepton + jets candidate events they measure: M{sub top} = 171.9 ± 1.7 (stat. + JES) ± 1.1 (other sys.) GeV/c2 = 171.9 ± 2.0 GeV/c2. The measurement features a robust treatment of the systematic uncertainties, correlated between the two channels and develops techniques for a future top quark mass measurement simultaneously in all decay channels. Measurements of the W boson mass and the top quark mass provide a constraint on the mass of the yet unobserved Higgs boson. The Higgs boson mass implied by measurement presented here is higher than Higgs boson mass implied by previously published, most precise CDF measurements of the top quark mass in lepton + jets and dilepton channels separately.
Download or read book Measurement of the Top Quark Pair Production Cross-section in the Dilepton Channel Using Lepton Plus Track Selection and Identified B-jets written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Using 1.0 fb^{-1} of data collected by the Collider Detector at Fermilab (CDF) from Run II of the Fermilab Tevatron, we measure the top-antitop production cross-section in events with two leptons, significant missing transverse energy, and at least jets, at least one of which is identified as a b-jet. As the Run II dataset grows, more stringent tests of Standard Model predictions for the top quark sector are becoming possible. The dilepton channel, where both top quarks decay t-> W b ->l nu b, is of particular interest due to its high purity. Use of an isolated track as the second lepton significantly increases the dilepton acceptance, at the price of some increase in background, particularly from W + jets events where one of the jets is identified as a lepton. To control the increase in background we add to the event selection the requirement that at least one of the jets be identified as a b-jet, reducing the background contribution from all sources. Assuming a branching ratio of BR(W->l nu) = 10.8% and a top mass of m_top = 175 GeV/c^{2} the measured cross-section is sigma = (10.5 +/- 1.8 stat. +/- 0.8 syst. +/- 0.6 lumi.) pb.
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ISBN 13 :
Total Pages : 214 pages
Book Rating : 4.:/5 (925 download)
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 .
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ISBN 13 :
Total Pages : 7 pages
Book Rating : 4.:/5 (873 download)
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:
Author : John Freeman
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ISBN 13 :
Total Pages : 3 pages
Book Rating : 4.:/5 (316 download)
Download or read book CDF Measurement of the Top Quark Mass in the Lepton + Jets Channel Using the Multivariate Template Method written by John Freeman and published by . This book was released on 2004 with total page 3 pages. Available in PDF, EPUB and Kindle. Book excerpt: The authors measure the mass of the top quark using 162 pb{sup -1} of data collected by the CDF experiment at FNAL in Run II. The decay chain t{bar t} {yields} bq{bar q}{bar b}lv is studied using a novel technique called the Multivariate Template Method (MTM). Using this technique they obtain a result of M{sub top} = 179.6{sub -6.3}{sup +6.4} {+-} 6.8 GeV/c{sup 2} for the top quark.
