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Production of Gauge Bosons at the Tevatron

Description: The CDF and D0 collaborations have used recent data taken at the Tevatron to perform QCD tests with W and Z bosons decaying leptonically. D0 measures the production cross section times branching ratio for W and Z bosons and determines the branching ratio B(W {yields} l{nu}) = (10.43 {+-} 0.44)% (l = e, {mu}). This also gives an indirect measurement of the total width of the W boson: {Gamma}{sub W} = 2.16 {+-} 0.09 GeV. The W cross section times branching ratio into tau leptons is measured to be {sigma}({anti p}p {yields} W + X)B(W {yields} {tau}{nu}) = 2.38{+-}0.13 nb, from which the ratio of the coupling constants is determined: g{sub {tau}}{sup W}/g{sub e}{sup W} = 1.004 {+-} 0.019 {+-} 0.026. D0`s measurement of the differential d{sigma}/dP{sub T} distribution for the Z boson decaying to electrons, discriminates between different phenomenologic vector boson production models. CDF measures the cross section for the Drell-Yan continuum, and extracts improved limits on compositeness scales for quarks and leptons of {Lambda}{sub ql} {approximately} 3 - 6 TeV, depending on the model. Studies of W + Jet production at CDF and D0 find that the QCD prediction underestimates the production rate of W + 1 Jet events by about a factor of 2 as measured by both collaborations.
Date: June 1, 1997
Creator: Gerber, C.E. & Collaborations, CDF and D0
Partner: UNT Libraries Government Documents Department

Trilinear gauge couplings at the Fermilab Tevatron

Description: Recent trilinear gauge boson couplings measurements by the CDF and D0 Collaborations at the Fermilab Tevatron are presented. The measurements were done by analyzing diboson production in multiple decay channels and final states. No deviations from the Standard Model description of the WWZ, WW{gamma}, ZZ{gamma} and Z{gamma}{gamma} vertices were found. Limits on anomalous gauge couplings set by these analyses are the tightest available to date.
Date: October 1, 1997
Creator: Landsberg, G.
Partner: UNT Libraries Government Documents Department

Measurement of the W boson mass at the Tevatron

Description: Presented are measurements of the W boson mass from the D0 and CDF collaborations at the Tevatron from the 1994-1996 run. The W events are produced in p{anti p} collisions at {radical}s = 1.8 TeV. The W mass extracted from W {yields} e{nu} decays at D0 is determined to be 80.45 {+-} 0.12 GeV; and from W {yields} {mu}{nu} decays at CDF is 80. 43 {+-} 0.16 GeV. The world average W mass from the hadron collider measurements is 80.41 {+-} 0.09 GeV.
Date: August 1, 1997
Creator: Flattum, E.
Partner: UNT Libraries Government Documents Department

W, Z + jets at Tevatron

Description: We report the production jet cross-sections and properties in W and Z events using data from collisions with {radical}s = 1800 GeV at Fermilab Tevatron. Observed distributions in general agree with predictions of leading order QCD matrix element calculations with added gluon radiations and simulated parton fragmentations; however, some limitations of LO QCD predictions are also observed. The cross-section ratio of W + {>=} 1 jet events to inclusive W events is reported and compared with next-to-the-leading order QCD expectations. Good agreement between data and theory is seen. The color coherence effects are also observed in W+ jets events.
Date: May 3, 1999
Creator: Chang, Paoti
Partner: UNT Libraries Government Documents Department

Top quark physics: Overview

Description: In this presentation I will primarily focus on top quark physics but I will include a discussion of the W-boson mass and the possibility of discovering a light Higgs boson via associated production at the Tevatron.
Date: January 1, 1998
Creator: Parke, S.
Partner: UNT Libraries Government Documents Department

W {right arrow} {tau}{nu} and Gamma{sub W} studies at the Tevatron collider

Description: The most recent results on the studies of the W properties, namely of the process W{yields}{tau}{nu} and of the {Gamma}{sub W} measurements performed in {anti p}p collisions at {radical}s=1800 GeV, are reported. The data are from the two experiments operating at the Tevatron Collider, CDF and DO.
Date: May 3, 1999
Creator: Rimondi, F.
Partner: UNT Libraries Government Documents Department

Vector boson pair production and trilinear gauge boson couplings - Results from the Tevatron

Description: Direct measurements of vector boson pair production processes and trilinear gauge boson couplings have been conducted by the CDF and D0 Collaborations. Preliminary results from searches for anomalous WW/WZ {yields} {mu}{nu} jet jet and WZ {yields} eee{nu} production are presented. 95% CL anomalous coupling limits from previously published D0 results are -0.20< {lambda} < 0.20 ({Delta}{kappa} = 0) and -3.0<{Delta}{kappa} < 0:43 ({lambda} = 0) for {Lambda} = 2000 GeV where the WW{gamma} couplings are assumed to equal the WWZ couplings. Combined D0 + LEP experiment anomalous coupling limits are presented for the #12;rst time. 95% CL limits are -0.16 < {lambda}{sub {gamma}} < 0:10 ({Delta}{kappa} = 0) and -0.15< {Delta}{kappa}{sub {gamma}}#20; < 0:41 ({lambda} = 0) under the assumption that the couplings are related by the \HISZ" constraints. 95% CL anomalous ZZ{gamma} and Z{gamma}{gamma} coupling limits from D0 are jh{sup Z}{sub 30} j < 0:36 (h{sup Z}{sub 40 = 0) and jh{sup Z}{sub 40} j < 0:05 (h{sup Z}{sub 30} = 0) for {Lambda} = 750 GeV. CDF reports the first observation of a ZZ event. Prospects for Run II are discussed.
Date: October 1, 1998
Creator: Diehl, H. T.
Partner: UNT Libraries Government Documents Department

New Tevatron measurements of the W boson mass

Description: The CDF and D0 Collaborations obtain new measurements of the W boson mass using data taken between 1994 and 1996. CDF updates the previous result obtained from W {yields} {mu}{nu} decays, reducing many systematic uncertainties, and performs a new measurement using a high statistics sample of W {yields} e{nu} events; combining these measurements with the previous ones yields M<sub>W</sub><sup>CDF</sup> =80.433 &plusmn; 0.079 GeV/c &sup2;. D0 also extends the previous result, based on central electron events, by including events with electrons landed in the forward calorimeters; the combined D0 result is M<sub>W</sub><sup>D0</sup> = 80.474 &plusmn; 0.093 GeV/c &sup 2;. The numbers obtained by the two experiments can be combined together with the older UA2 one (M<sub>W</sub><sup>UA2</sup> = 80.36 &plusmn; 0.37 GeV/c &sup2;), by assuming a 25 MeV/c &sup2; common error, to yield a hadron collider average of M<sub>W</sub> =80.448 &plusmn; 0.062 GeV/c &sup2;.
Date: June 29, 1999
Creator: Dorigo, T.
Partner: UNT Libraries Government Documents Department

New Tevatron measurements of the W boson mass

Description: New measurements of the W boson mass from the two Tevatron experiments, CDF and D0 are presented. The results are from the 1994-1995 Tevatron run, and based on integrated luminosities of 82 pb<sub>-1</sub> (D0) and 90 pub<sub>-1</sub> (CDF), from p{anti p} collisions at {radical}s=1.8 TeV. These new measurements when combined with previous published measurements yield a Tevatron W mass value of 80.450 &plusmn; 0.063 GeV.
Date: June 29, 1999
Creator: Lancaster, Mark
Partner: UNT Libraries Government Documents Department

Constraints on PDFs from W and Z rapidity distributions at CDF

Description: The rapidity distributions of W and Z bosons produced in proton anti-proton collisions at CDF are presented. The rapidity distribution of Z bosons, measured for the first time over the entire kinematic range, is better described by NLO QCD (and also by QCD with gluon resummation) than by leading order QCD. The W charge asymmetry data as a function of rapidity strongly constrain the ratio of d and u quark momentum distributions in the proton over the x range of 0.006 to 0.34. The W data are used to rule out recently proposed models for charge and flavor symmetry violation of the sea quark distributions in the nucleon.
Date: July 20, 1999
Creator: Bodek, A.
Partner: UNT Libraries Government Documents Department

Test of structure functions using lepton pairs: W-charge asymmetry and Drell-Yan production at CDF

Description: The charge asymmetry of leptons from W-bosons and the Drell-Yan cross section of massive charged lepton pairs from {gamma}*/Z-bosons produced in p{anti p} collisions are measured using 110 pb{sup -1} of collisions taken by the Collider Detector at Fermilab (CDF) during 1992-95. The W-asymmetry measurement provides a precise constraint of the slope of the quark distribution ratio, d(x)/u(x), over the x range of 0.006 to 0.34. The Drell-Yan measurement spans the mass range of 11 to 500 GeV/c{sup 2}, and QCD calculations using recent parton distribution functions are in good agreement with it.
Date: October 1, 1998
Creator: Sakumoto, W.
Partner: UNT Libraries Government Documents Department

Probing quartic couplings through three gauge boson production at an e{sup +}e{sup {minus}} linear collider

Description: We explore the capability of a 500 or 1000 GeV e{sup +} e{sup {minus}} linear collider to measure anomalous quartic gauge boson couplings. In the framework of a non-linear effective Lagrangian with a custodial SU(2) symmetry, there are only two next-to-leading order operators which contribute to quartic, but not to two- and three-gauge boson interactions. The limits on the coefficients of these operators from present and future e{sup +} e{sup {minus}} colliders are compared with those available from other sources.
Date: November 22, 1996
Creator: Dawson, S.; Likhoded, A.; Valencia, G. & Yushchenko, O.
Partner: UNT Libraries Government Documents Department

Strong WW scattering chiral lagrangians, unitarity and resonances

Description: Chiral lagrangians provide a model independent description of the strongly interacting symmetry breaking sector. In this work, first we review the LHC sensitivity to the chiral parameters (in the hardest case of non-resonant low-energy WW scattering). Later we show how to reproduce or predict the resonance spectrum by means of dispersion theory and the inverse amplitude method. We present a parameter space scan that covers many different strong WW scattering scenarios.
Date: August 1, 1996
Creator: Pelaez, J.R.
Partner: UNT Libraries Government Documents Department

New particle searches at the Tevatron (I)

Description: Searches for new particles in p{ovr p} collisions at {radical}s = 1.8 TeV are ongoing at the Fermilab Tevatron collider using the CDF and D0 detectors. Current results from searches for heavy charged vector bosons and fourth generation quarks as well as for Supersymmetric partners of Standard Model quarks and gluons are presented. 11 refs., 4 figs.
Date: May 1, 1996
Creator: Gallas, E.
Partner: UNT Libraries Government Documents Department

Measurement of M{sub ital W} using the transverse mass ratio of W and Z

Description: We report on the measurement of W boson mass from a determination of the ratio of the transverse masses of {ital W} and {ital Z} using the DO detector at the Fermilab Tevatron {ital p{anti p}} Collider operating at {radical}{ital s} = 1.8 TeV. The analysis is a preliminary result based on a partial data sample of 13 pb{sup -1} using W {r_arrow} {ital e{sup -}{mu}{sup +}} and Z {r_arrow} {ital e{sup -}e{sup +}} decays. The mass ratio can also be extracted by comparing the shapes of the electron E{sub T} and & distribution from W and Z decays.
Date: December 31, 1996
Creator: Rajagopalan, S.; Rijssenbeek, M. & Collaboration, D0
Partner: UNT Libraries Government Documents Department

Measurement of W + 1 jet/W + 0 jets cross sections

Description: A preliminary measurement of the ratio W + 1 Jet/W + 0 Jets in {ital p}{ital {anti p}} collisions at {radical}s = 1800 GeV is presented. A comparison to next-to-leading order QCD finds the theory to be well below the experimental ratio even after accounting for the systematic uncertainties of the measurement. In addition, a study of both the measured and theoretical ratios as a function of minimum jet transverse energy (E{sub T}) shows that the theoretical predictions are systematically lower than the data.
Date: August 1996
Creator: Guglielmo, G.
Partner: UNT Libraries Government Documents Department

Search for ZX {yields} {nu}{anti {nu}} b {anti b} Events in the D-Zero Detector

Description: We report on a search for a new particle, X, decaying via X {yields} b{anti b}, made through associated production with a Z boson. We use data collected with the D0 detector operating at the Fermilab Tevatron p{anti p} collider with {radical}s = 1.8 TeV. We utilize muon-tagged jets to identify b-quarks and the {nu}{anti {nu}} channel to detect Z bosons. Preliminary results on cross section limits for X masses between 90 GeV/c{sup 2} and 180 GeV/c{sup 2} are presented.
Date: October 1, 1997
Creator: Abbott, B.
Partner: UNT Libraries Government Documents Department

Search for heavy neutral gauge bosons at D-Zero

Description: We report preliminary results of a search for a heavy neutral gauge boson, Z`, using the decay channel Z` {yields} ee . The data were collected with the D0 detector at the Fermilab Tevatron during the 1994-1995 p{anti p} collider run at {radical}s = 1.8 TeV and correspond to an integrated luminosity of {approx} 90 pb{sup -1}. Limits are set on the cross section times branching ratio for the process {anti p}p {yields} Z` {yields} ee as a function of the Z` mass. We exclude the existence of a heavy neutral gauge boson of mass less than 660 GeV/c{sup 2} (95% CL), assuming a Z` with the same coupling strengths to quarks and leptons as the standard model Z boson. Combining this analysis with DO`s 1992-1993 data set increases the limit to m{sub Z`} > 670 GeV/c{sup 2}.
Date: October 1, 1997
Creator: Abbott, B.
Partner: UNT Libraries Government Documents Department

W and Z production cross sections at D0

Description: We present a measurement of the production cross section times branching ratio for {ital W} and {ital Z} bosons decaying to the electrons or muons in {ital p}{ital {anti p}} collisions at {radical}s = 1.8 TeV using data recorded at the Tevatron during the 1994-1995 collider run. Using the ratio of these two measurements, we derive the {ital W} leptonic branching fraction and the width of the {ital W} boson.
Date: November 1, 1996
Creator: Tarazi, J.N.
Partner: UNT Libraries Government Documents Department

Recent Electroweak Results from the Tevatron

Description: Recent electroweak results from the CDF and D0 Collaborations at the Fermilab Tevatron Collider are presented. After a brief description of the D0 measurements of W/Z production cross sections, W width, W mass and W {r_arrow} {tau}{nu} decay, the CDF result on W(p{sub T}) distribution is outlined. The comprehensive search for anomalous gauge couplings by D0 in 1992-96 data is presented along with a detailed description of the WW/WZ {r_arrow} {mu}{nu}jj channel.
Date: April 8, 1999
Creator: Gounder, Krishnaswamy
Partner: UNT Libraries Government Documents Department