Top Quark Mass Measurement Using the Template Method at CDF.

Top Quark Mass Measurement Using the Template Method at CDF.
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ISBN-10 : OCLC:873644334
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Rating : 4/5 (34 Downloads)

Synopsis Top Quark Mass Measurement Using the Template Method at CDF. by :

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.

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.

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.
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Total Pages : 18
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ISBN-10 : OCLC:316308140
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Rating : 4/5 (40 Downloads)

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

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}.

Measurement of the Top Quark Mass at CDF Using the Template Method in the Lepton + Jets Channel

Measurement of the Top Quark Mass at CDF Using the Template Method in the Lepton + Jets Channel
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Publisher :
Total Pages : 174
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ISBN-10 : OCLC:727357863
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Rating : 4/5 (63 Downloads)

Synopsis Measurement of the Top Quark Mass at CDF Using the Template Method in the Lepton + Jets Channel by :

A measurement of the top quark mass in p{bar p} collisions at (square root)s = 1.96 TeV is presented. The analysis uses a template method, in which the overconstrained kinematics of the Lepton+Jets channel of the t{bar t} system are used to measure a single quantity, the reconstructed top quark mass, that is strongly correlated with the true top quark mass. in addition, the dijet mass of the hadronically decaying W boson is used to constrain in situ the uncertain jet energy scale in the CDF detector. Two-dimensional probability density functions are derived using a kernel density estimate-based machinery. Using 1.9 fb−1 of data, the top quark mass is measured to be 171.8{sub -1.9}{sup +1.9}(stat.) ± 1.0(syst.)GeV/c2.

Measurements of the Top-quark Decay Width and Mass at CDF Using the Template Method

Measurements of the Top-quark Decay Width and Mass at CDF Using the Template Method
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Publisher :
Total Pages : 147
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ISBN-10 : OCLC:962178651
ISBN-13 :
Rating : 4/5 (51 Downloads)

Synopsis Measurements of the Top-quark Decay Width and Mass at CDF Using the Template Method by :

Measurements of the top quark decay width and mass are presented using the tt events produced in p p collisions at Fermilab's Tevatron collider and collected by the CDF II detector. A data sample corresponding to 4.3 fb-1 of integrated luminosity is used for the top quark width measurement. Two estimators, the reconstructed top quark mass and the mass of hadronically decaying W boson that comes from the top-quark decay are reconstructed for each event and compared with templates of different input top quark widths and deviations from nominal CDF jet energy scale ([Delta]JES) to perform a simultaneous fit for both parameters. [Delta]JES is used for the in situ calibration of the jet energy scale at CDF. By applying a Feldman-Cousins limit-setting approach, we establish an upper limit at 95% confidence level (CL) of [Gamma]top

Measurement of the Top Quark Mass at CDF Using the Ǹeutrino Phi Weighting' Template Method on a Lepton Plus Isolated Track Sample

Measurement of the Top Quark Mass at CDF Using the Ǹeutrino Phi Weighting' Template Method on a Lepton Plus Isolated Track Sample
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Total Pages : 17
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ISBN-10 : OCLC:1061407907
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Rating : 4/5 (07 Downloads)

Synopsis Measurement of the Top Quark Mass at CDF Using the Ǹeutrino Phi Weighting' Template Method on a Lepton Plus Isolated Track Sample by :

We present a measurement of the top quark mass with t{bar t} dilepton events produced in p{bar p} collisions at the Fermilab Tevatron (√s = 1.96 TeV) and collected by the CDF II detector. A sample of 328 events with a charged electron or muon and an isolated track, corresponding to an integrated luminosity of 2.9 fb−1, are selected as t{bar t} candidates. To account for the unconstrained event kinematics, we scan over the phase space of the azimuthal angles (?{sub {nu}1},?{sub {nu}2}) of neutrinos and reconstruct the top quark mass for each?{sub {nu}1},?{sub {nu}2} pair by minimizing a?2 function in the t{bar t} dilepton hypothesis. We assign?2-dependent weights to the solutions in order to build a preferred mass for each event. Preferred mass distributions (templates) are built from simulated t{bar t} and background events, and parameterized in order to provide continuous probability density functions. A likelihood fit to the mass distribution in data as a weighted sum of signal and background probability density functions gives a top quark mass of 165.5{sub -3.3}{sup +3.4}(stat.)±3.1(syst.) GeV/c2.

Measurement of the Top Quark Mass Using Template Methods on Dilepton Events in P Anti-p Collisions at S**ư

Measurement of the Top Quark Mass Using Template Methods on Dilepton Events in P Anti-p Collisions at S**ư
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Total Pages : 52
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ISBN-10 : OCLC:1060825737
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Rating : 4/5 (37 Downloads)

Synopsis Measurement of the Top Quark Mass Using Template Methods on Dilepton Events in P Anti-p Collisions at S**ư by :

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.

Top Quark Mass Measurement

Top Quark Mass Measurement
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Publisher :
Total Pages : 43
Release :
ISBN-10 : OCLC:727351194
ISBN-13 :
Rating : 4/5 (94 Downloads)

Synopsis Top Quark Mass Measurement by :

The top quark is the heaviest elementary particle. Its mass is one of the fundamental parameters of the standard model of particle physics, and an important input to precision electroweak tests. This thesis describes three measurements of the top-quark mass in the dilepton decay channel. The dilepton events have two neutrinos in the final state; neutrinos are weakly interacting particles that cannot be detected with a multipurpose experiment. Therefore, the signal of dilepton events consists of a large amount of missing energy and momentum carried off by the neutrinos. The top-quark mass is reconstructed for each event by assuming an additional constraint from a top mass independent distribution. Template distributions are constructed from simulated samples of signal and background events, and parametrized to form continuous probability density functions. The final top-quark mass is derived using a likelihood fit to compare the reconstructed top mass distribution from data to the parametrized templates. One of the analyses uses a novel technique to add top mass information from the observed number of events by including a cross-section-constraint in the likelihood function. All measurements use data samples collected by the CDF II detector.

Top Quark Physics at Hadron Colliders

Top Quark Physics at Hadron Colliders
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Publisher : Springer Science & Business Media
Total Pages : 166
Release :
ISBN-10 : 9783540710608
ISBN-13 : 3540710604
Rating : 4/5 (08 Downloads)

Synopsis Top Quark Physics at Hadron Colliders by : Arnulf Quadt

This will be a required acquisition text for academic libraries. More than ten years after its discovery, still relatively little is known about the top quark, the heaviest known elementary particle. This extensive survey summarizes and reviews top-quark physics based on the precision measurements at the Fermilab Tevatron Collider, as well as examining in detail the sensitivity of these experiments to new physics. Finally, the author provides an overview of top quark physics at the Large Hadron Collider.