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Boson pair production and triple gauge couplings

Description: The D0 and CDF Collaborations measure boson pair production including W{gamma}, WW, WZ, ZZ and Z{gamma} production in p{anti p} collisions at {radical}s = 1800 GeV. New results, from direct measurements, are described including W{gamma}, WW, and Z{gamma} production cross sections and limits on non-Standard Model triple gauge boson couplings. The limits on anomalous WW{gamma}, WWZ, Z{gamma}{gamma} and ZZ{gamma} couplings are the most restrictive available. Prospects for Run II are discussed.
Date: June 1, 1997
Creator: Diehl, H.T. & Collaborations, D0 and CDF
Partner: UNT Libraries Government Documents Department

First Run II Measurement of the W Boson Mass

Description: We describe a measurement of the W boson mass m{sub W} using 200 pb{sup -1} of {radical}s = 1.96 TeV p{bar p} collision data taken with the CDF II detector. With a sample of 63,964 W {yields} e{nu} candidates and 51,128 W {yields} {mu}{nu} candidates, we measure m{sub W} = [80.413 {+-} 0.034(stat.) {+-} 0.034 (sys.) = 80.413 {+-} 0.048] GeV/c{sup 2}. This is the single most precise m{sub W} measurement to date. When combined with other measured electroweak parameters, this result further constrains the properties of new unobserved particles coupling to W and Z bosons.
Date: August 1, 2007
Creator: Aaltonen, T.; Phys., /Helsinki Inst. of; Abulencia, A.; /Illinois U., Urbana; Adelman, J.; /Chicago U., EFI et al.
Partner: UNT Libraries Government Documents Department

Measurement of the W boson mass and width using a novel recoil model

Description: This dissertation presents a direct measurement of the W boson mass (M{sub W}) and decay width ({Lambda}{sub W}) in 1 fb{sup -1} of W {yields} e{nu} collider data at D0 using a novel method to model the hadronic recoil. The mass is extracted from fits to the transverse mass M{sub T}, p{sub T}(e), and E{sub T} distributions. The width is extracted from fits to the tail of the M{sub T} distribution. The electron energy measurement is simulated using a parameterized model, and the recoil is modeled using a new technique by which Z recoils are chosen from a data library to match the p{sub T} and direction of each generated W boson. We measure the the W boson mass to be M{sub W} = 80.4035 {+-} 0.024(stat) {+-} 0.039(syst) from the M{sub T}, M{sub W} = 80.4165 {+-} 0.027(stat) {+-} 0.038(syst) from the pT(e), and MW = 80.4025 {+-} 0.023(stat) {+-} 0.043(syst) from the E{sub T} distributions. {Lambda}{sub W} is measured to be {Lambda}{sub W} = 2.025 {+-} 0.038(stat) {+-} 0.061(syst) GeV.
Date: January 1, 2009
Creator: Wetstein, Matthew J. & U., /Maryland
Partner: UNT Libraries Government Documents Department

Measurements of the Trilinear Gauge Boson Couplings from Diboson Production at D0

Description: The most recent measurements of the trilinear gauge boson couplings from the diboson production at the D0 experiment has been presented. The analyzed final states are Z{gamma} {yields} {nu}{nu}{gamma}, WW {yields} l{nu}l{prime}{nu}, and WW+WZ {yields} l{nu}jj. We also present results obtained combining all final states involving the W boson. These results represent the most stringent limits set to date at the hadron collider.
Date: October 1, 2009
Creator: Sekaric, Jadranka
Partner: UNT Libraries Government Documents Department

Measurement of the t anti-t production cross section in p anti-p collisions at s**(1/2) = 1.96-TeV

Description: We present the measurement of the t{bar t} cross section in the lepton plus jets channel with {ge} 1 and {ge} 2 secondary vertex tags. We use the scalar sum of transverse energies of the event (H{sub T}) to discriminate t{bar t} from the other backgrounds. We also use the transverse mass of the leptonic W-boson (M{sub T}{sup W}) to further reduce the Non-W backgrounds. We use a combination of data and Monte Carlo to estimate the backgrounds from electroweak processes, single top, fake leptons, W+ Light Flavor fake tags, and real W+ Heavy Flavor production. We obtain a value of {sigma} {sub {ge}1} = 8.7{sub -0.9}{sup +0.9}(stat){sub -0.9}{sup +1.2}(sys) pb for the {ge}1 tag cross section, and {sigma}{sub {ge}2} = 8.7{sub -1.6}{sup +1.8}(stat){sub -1.3}{sup +1.9}(sys) pb for the {ge}2 tag cross section. The authors also present a measurement of the t{bar t} cross section by fitting the N{sub jet} spectrum. They combine the =1 and {ge}2 tag cross sections to obtain {sigma}{sub t{bar t}} = 8.9{sub -0.9}{sup +0.9}(stat){sub -1.3}{sup +1.4}(syst)pb.
Date: August 1, 2005
Creator: Rappoccio, Salvatore Rocco
Partner: UNT Libraries Government Documents Department

Measurement of the W boson mass

Description: The authors present a measurement of the W boson mass in W {yields} e{nu} decays using 1 fb{sup -1} of data collected with the D0 detector during Run II of the Fermilab Tevatron collider. With a sample of 499830 W {yields} e{nu} candidate events, they measure M{sub W} = 80.401 {+-} 0.043 GeV. This is the most precise measurement from a single experiment.
Date: August 1, 2009
Creator: Abazov, Victor Mukhamedovich; Abbott, Braden Keim; Abolins, Maris A.; Acharya, Bannanje Sripath; Adams, Mark Raymond; Adams, Todd et al.
Partner: UNT Libraries Government Documents Department

Measuring the W boson mass at the Tevatron

Description: The measurement of the mass of the W boson is one of the prime goals of the Tevatron experiments. In this contribution, a review is given of the most recent determinations of the W boson mass (m{sub W}) at the Tevatron. The combined Tevatron result, m{sub W} = 80.420 {+-} 0.031 GeV, is now more precise than the combined LEP result, leading to a world average value of m{sub W} = 80.399 {+-} 0.023 GeV.
Date: September 1, 2010
Creator: Sanders, M.P. & U., /Munich
Partner: UNT Libraries Government Documents Department

Ratio method of measuring $w$ boson mass

Description: This dissertation describes an alternative method of measuring the W boson mass in D0 experiment. Instead of extracting M{sub W} from the fitting of W {yields} e{nu} fast Monte Carlo simulations to W {yields} e{nu} data as in the standard method, we make the direct fit of transverse mass between W {yields} e{nu} data and Z {yields} ee data. One of the two electrons from Z boson is treated as a neutrino in the calculation of transverse mass. In ratio method, the best fitted scale factor corresponds to the ratio of W and Z boson mass (M{sub W}/M{sub Z}). Given the precisely measured Z boson mass, W mass is directly fitted from W {yields} e{nu} and Z {yields} ee data. This dissertation demonstrates that ratio method is a plausible method of measuring the W boson mass. With the 1 fb{sup -1} D0 Run IIa dataset, ratio method gives M{sub W} = 80435 {+-} 43(stat) {+-} 26(sys) MeV.
Date: August 1, 2010
Creator: Guo, Feng & /SUNY, Stony Brook
Partner: UNT Libraries Government Documents Department

Tevatron results on gauge boson couplings

Description: Direct measurements of the trilinear gauge boson couplings by the CDF and D0 collaborations at Fermilab are reviewed. Limits on the anomalous couplings were obtained at a 95% CL from four diboson production processes: W{gamma} production with the subsequent W boson decay to e{nu} or {mu}{nu}, WW production with both the W boson decaying to e{nu} or {mu}{nu}, WW/WZ production with one of the gauge bosons decaying leptonically and the other gauge boson decaying to two jets, and Z{gamma} production with the subsequent Z boson decay to ee, {mu}{mu}, or {nu}{nu}. Limits were also obtained by a combined fit to W{gamma}, WW{yields}dileptons and WW/WZ semileptonic data samples.
Date: June 1, 1997
Creator: Yasuda, T. & Collaborations, CDF and D0
Partner: UNT Libraries Government Documents Department

Measurements of trilinear gauge boson couplings

Description: Direct measurements of the trilinear gauge boson couplings by the D0 collaboration at Fermilab are reported. Limits on the anomalous couplings were obtained at a 95% CL from four diboson production processes: W{gamma} production with the W boson decaying to e{nu} or {mu}{nu}, WW production with both of the W bosons decaying to e{nu} or {mu}{nu}, WW/WZ production with one W boson decaying to e{nu} and the other W or Z boson decaying to two jets, and Z{gamma} production with the Z boson decaying to ee, {mu}{mu}, or {nu}{nu}. Limits were also obtained from a combined fit to W{gamma}, WW {yields} dileptons and WW/WZ {yields} e{nu}jj data samples.
Date: October 1, 1997
Creator: Abbott, B.
Partner: UNT Libraries Government Documents Department

Recent results in high pT physics from CDF

Description: The authors present the most recent high p{sub T} results from the CDF experiment using p{bar p} collisions at {radical}s = 1.96 TeV produced at the Tevatron Collider at Fermilab. They summarize results in electroweak physics, top physics and searches for physics beyond the Standard Model. Many measurements of important signals like W boson, Z boson, and the top quark have been reestablished. Taking advantage of the increase in energy and detector upgrades, these measurements already begin to be competitive with previous results.
Date: March 9, 2004
Creator: Veramendi, G.
Partner: UNT Libraries Government Documents Department

How to calibrate the jet energy scale?

Description: Top quarks dominantly decay into b-quark jets and W bosons, and the W bosons often decay into jets, thus the precise determination of the jet energy scale is crucial in measurements of many top quark properties. I present the strategies used by the CDF and D0 collaborations to determine the jet energy scale. The various cross checks performed to verify the determined jet energy scale and evaluate its systematic uncertainty are also discussed.
Date: January 1, 2006
Creator: Hatakeyama, K. & U., /Rockefeller
Partner: UNT Libraries Government Documents Department

Combination of CDF and D0 results on the W boson mass and width

Description: The results on the direct measurements of the W-boson mass and width, based on the data collected by the Tevatron experiments CDF and D{sup -} at Fermilab are summarized and combined. The CDF Run-0 (1988-1889) and Run-I (1992-1995) results have been re-averaged using the BLUE method and combined with Run-I D{sup -} results and the latest published results from CDF taken from the first period of Run-II (2001-2004). The results are corrected to have consistency between the parton distribution functions and electroweak parameters. The resulting Tevatron averages for the mass and total decay width of the W boson are: M{sub W} = 80432 {+-} 39 MeV and {Lambda}{sub W} = 2056 {+-} 62 MeV. The inclusion of a preliminary Run-II measurement of {Lambda}{sub W} from D{sup -}0 gives {Lambda}{sub W} = 2050 {+-} 58 MeV.
Date: August 1, 2008
Creator: Group, Tevatron Electroweak Working
Partner: UNT Libraries Government Documents Department

Measurement of the W boson helicity in top quark decays

Description: A measurement of the fraction, f{sup +}, of right-handed W bosons produced in top quark decays is presented. This analysis is based on a sample corresponding to an integrated luminosity of 370 pb{sup -1}, collected by the D0 detector at the Fermilab Tevatron p{bar p} Collider at {radical}s = 1.96 TeV. The helicity angle, {theta}*, is reconstructed for each lepton. f{sup +} is determined by comparing the cos {theta}* distribution from the data with that for the expected background and signal for various values of f{sup +}. The fraction of longitudinal W bosons, f{sup 0}, is assumed to be 0.7 as predicted by the standard model. This yields f{sup +} = 0.109 {+-} 0.094 (stat) {+-} 0.063 (syst), consistent with the standard model prediction of f{sup +} = 3.6x 10{sup -4}. The possibility that both f{sup +} and f{sup 0} stray from standard model values is also investigated. In this case cos {theta}* distributions for each possible W helicity state, along with the backgrounds, are fit to the cos {theta}* distribution for the data. The best fit values are f{sup +} = 0.82 {+-} 0.30(stat) and f{sup 0} = -0.58 {+-} 0.50(stat).
Date: August 1, 2007
Creator: Gmyrek, Bryan David & U., /Arizona
Partner: UNT Libraries Government Documents Department

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

Description: 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}.
Date: May 1, 2006
Creator: Adelman, Jahred A.; Arguin, J.F.; Bellettini, G.; Brubaker, E.; Budagov, J.; Chlachidze, G. et al.
Partner: UNT Libraries Government Documents Department

Search for V+A current in top quark decay in p anti-p collisions at s**(1/2) = 1.96-TeV

Description: The authors report an upper limit on the fraction of V + A current, f{sub V+A}, in top quark decays, using approximately 700 pb{sup -1} of p{bar p} collisions at {radical}s = 1.96 TeV acquired by the upgraded Collider Detector at Fermilab. For the decay t {yields} wb {yields} {ell}vb (where {ell} = e or {mu}), the invariant mass of the charged lepton and the bottom quark jet is sensitive to the polarization of the W boson. They determine f{sub V+A} = -0.06 {+-} 0.25 given a top quark mass of 175 GeV/c{sup 2}. They set an upper limit on f{sub V+A} of 0.29 at the 95% confidence level, which represents an improvement by a factor of two on the previous best direct limit.
Date: August 1, 2006
Creator: Abulencia, A.; Adelman, J.; Affolder, T.; Akimoto, T.; Albrow, M.G.; Ambrose, D. et al.
Partner: UNT Libraries Government Documents Department