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Search for anomalous WW and WZ production at D0

Description: We present a preliminary result from a search for anomalous WW and WZ production in p{bar p} collisions at {radical}s = 1.8 TeV using p{bar p} {yields} e{nu}jj events observed during the 1992-1993 run of the Fermilab Tevatron collider. A fit to the p{sub T} spectrum of W(e{nu}) yields direct limits on the CP-conserving anomalous WW{gamma} and WWZ coupling parameters of -0.89 < {Delta}{kappa} < 1.07 ({lambda} = 0) and -0.66 < {lambda} < 0.67 ({Delta}{kappa} = 0) at the 95% confidence level, assuming that the WWZ coupling parameters are equal to the WW{gamma} coupling parameters, and a form factor scale {Lambda} = 1.5 TeV.
Date: July 1, 1995
Creator: Abachi, S.
Partner: UNT Libraries Government Documents Department

Inclusive dimuon and b-quark production cross sections in p{bar p} collisions at {radical}s = 1.8 TeV

Description: We report on a preliminary measurement of the inclusive dimuon cross section in p{bar p} collisions at {radical}s = 1.8 TeV using the D0 detector at the Fermilab Tevatron. From these results, we extract the inclusive b-quark production cross section for the kinematic range {vert_bar}y{sup b}{vert_bar} < 1.0 and 9 GeV/c < p{sub T}{sup b min} < 25 GeV/c. The difference in azimuthal angle in the transverse plane for dimuon pairs from b{bar b} production is also shown.
Date: July 1, 1995
Creator: Abachi, S.; Abbott, B. & Abolins, M.
Partner: UNT Libraries Government Documents Department

Electroweak results from the Tevatron Collider

Description: We present the latest results on electroweak physics obtained from the analysis of p{anti p} collisions at {radical}s=1.8 TeV. The large data samples collected with the CDF and D0 detectors at the Tevatron collider allow measurements of the top quark mass to a 3% accuracy and of the W boson to a 0.1% accuracy. Many precision measurements that test the Standard Model and probe its possible extensions are also described.
Date: August 1, 1998
Creator: Dorage, T., Padova University and I.N.F.N.
Partner: UNT Libraries Government Documents Department

The search for squarks, gluinos and stop squarks in D0

Description: Searches through data collected by D0 at Fermilab during the 1992-- 1993 p {bar p} collider run for the supersymmetric partners to the quark and the gluon, the squark and gluino, including a low mass scalar top squark, are reviewed. A set of classic searches were conducted for missing E{sub T} plus jets signatures. No evidence of positive signals is reported, but limits are set on the squark and gluino masses.
Date: August 1, 1995
Creator: Claes, D.
Partner: UNT Libraries Government Documents Department

B physics at CDF.

Description: The CDF experiment at the Fermilab Tevatron has proven to be well suited for precision studies of b physics. Thanks to the excellent performance of the Tevatron Collider and the detector, CDF has accumulated very large data samples and roughly a decade of experience with b physics in p{bar p} collisions. With the much higher luminosities expected for the Main Injector era, the next decade promises to be an even more fruitful period for CDF. Here we offer a brief overview of issues in hadron-collider b physics and a summary of CDF's accomplishments and future plans.
Date: January 20, 1998
Creator: Wicklund, A. B.
Partner: UNT Libraries Government Documents Department

Search for light top squarks with the D{O} detector

Description: We present preliminary results of a search for pair produced top squarks, the supersymmetric partners to the top quark, under the assumption that the two-body decay {bar t}{sub 1} {yields} b{bar W}{sub 1} and three-body decay {bar t}{sub 1} {yields} bW{bar Z}{sub 1} are kinematically forbidden. This scenario is realized if {bar t}{sub 1} is considerably lighter than all other squarks as well as {bar W}{sub 1}, all {bar v}s, and the top quark. Such light top squarks will dominantly decay via {bar t}{sub 1} {yields} c{bar Z}{sub 1} yielding a signal of two acollinear jets with (E){sub T}. The data reported here were taken during the 1992-1993 run of the D0 detector at the Fermilab Tevatron p{bar p} collider operating at {radical}s = 1.8 TeV.
Date: July 1, 1995
Creator: Abachi, S.
Partner: UNT Libraries Government Documents Department

Studies of topological distributions of the three- and four-jet events in {bar p}p collisions at {radical}s = 1800 GeV with the D0 detector

Description: The global topologies of three- and four-jet events produced in {bar p}p interactions are described. the three- and four-jet events are selected from data recorded by the D0 detector at the Tevatron Collider operating at a center-of-mass energy of {radical}s = 1800 GeV. the measured normalized distributions of various topological variables are compared with parton-level predictions of the tree- level QCD calculations. The parton-level QCD calculations are found to be in good agreement with the data. The studies also show that the topological distributions of the different subprocesses involving different numbers of quarks are very similar and reproduce the measured distributions well.
Date: July 1, 1995
Creator: Abachi, S.
Partner: UNT Libraries Government Documents Department

Refrigerated hydrogen gas jet for the Fermilab antiproton accumulator

Description: A hydrogen gas jet has been built for use at Fermilab for the study of charmonium spectroscopy in proton-antiproton annihilations. The hydrogen gas jet is part of an upgrade to a previous experiment which ran in the Fermilab 1990-1991 fixed target program utilizing a jet cooled to 80 K with liquid nitrogen. The jet delivers a defined stream of hydrogen gas which travels through a series of vacuum chambers and then intersects the circulating antiproton beam. The goal of the upgrade is to provide a hydrogen gas stream at least twice as dense as used for the earlier experiment to increase the interaction rate and allow an improved study of rare processes. This is achieved by cooling the stream to below 30 K using a Gifford-McMahon refrigerator. The jet apparatus is designed to allow motion in the plane perpendicular to the gas stream as well as angular positioning at the jet nozzle to provide a means of optimizing the interaction rate. Two skimmers located in the vacuum chambers are used to define the gas stream dimensions. The jet target vacuum chambers require constant pumping with turbomolecular pumps. The vacuum space around the jet is designed to have a large system pumping speed so that the chamber pressure can be maintained below an absolute pressure of 1 Pa. The jet will operate in the next fixed target run at Fermilab. Details of the design and test results are discussed.
Date: July 1, 1995
Creator: Allspach, D.H.; Kendziora, C.L. & Marinelli, M.
Partner: UNT Libraries Government Documents Department

The E760 Jet Target: Measurements of performance at 77K

Description: In this report we describe the measurements performed on the E760 hydrogen Jet Target in order to some of the basic parameters of the system. These measurements were performed in the context of the upgrade program of the target for the successor experiment E835. Fermilab experiment E760 studied charmonium states formed in antiproton-proton annihilations. The antiproton-proton interactions were produced in a jet of hydrogen gas which intersected the antiproton beam coasting in the Fermilab Antiproton Accumulator. The results from E760 have shown that an increase in integrated luminosity by a factor of more than 5 is needed to complete the study of the charmonium spectrum. The E835 experiment is designed to achieve this by increasing the intensity of the antiproton beam and the density of the hydrogen-cluster-jet. This report is concerned with preparations for the work needed to increase the density of the hydrogen-cluster-jet.
Date: November 1, 1994
Creator: Boero, G.; Macri, M.; Robutti, E.; Allspach, D.; Kendziora, C. & Marinelli, M.
Partner: UNT Libraries Government Documents Department

CDF Run II Discovery reach for neutral MSSM higgs bosons via p pbar {right arrow}b b-bar {phi}{right arrow}b b-bar b b-bar

Description: In this paper we examine the CDF Run II discovery reach for neutral Higgs bosons via the process p{anti p} {yields} b {anti b} {phi} {yields} b {anti b}b {anti b}. The signature is a four jet final state with at least three b-tagged jets. Signal and background acceptances are estimated using the CDF Run I detector performance. b tagging efficiencies and fake tag rates are evaluated with new Run II increased detector geometrical acceptances. Total rates are estimated from present Run I data and from Monte Carlo. The results are interpreted within the framework of the minimal supersymmetric extension of the standard model (MSSM) and generalized in terms of a model independent enhancement factor.
Date: July 20, 1999
Creator: Valls, J.A.
Partner: UNT Libraries Government Documents Department

Multi-hadron final states.

Description: This summary aims to highlight major results and insights gained from recent studies of hadronic final states in ep, p{bar p}, e{sup +}e{sup -}, as well as relevant theoretical developments, presented in the Multi-hadron final states parallel sessions of the DIS2002 workshop held in Krakow, Poland in May 2002.
Date: August 29, 2002
Creator: Repond, J.
Partner: UNT Libraries Government Documents Department

A measurement of the top-antitop production cross section in the dimuon final state with the D0 detector for proton-antiproton collisions as s**(1/2) = 1.96 TeV

Description: A measurement of the top pair production cross section in the dimuon final state for proton-antiproton collisions at ps = 1:96 TeV is presented. Approximately 420 pb{sup -1} of data collected with the Run II D{O} detector are used for this measurement. Two data events are observed with a total expected signal plus background yield of 3.6 events. Assuming a top mass of 175 GeV, the measured cross section is: {sigma}{sub {bar u}} = 3.13{sup +4.17}{sub -2.60}(stat){sup +0.92}{sub -0.86}(sys){+-}0.19(lumi)pb, which is consistent with a NNLO prediction of 6.77 {+-} 0.42 pb.
Date: December 1, 2006
Creator: Burke, Susan Elizabeth & U., /Arizona
Partner: UNT Libraries Government Documents Department

Hybrid bubble chamber study of anti-p p interactions at 75-GeV/c

Description: We propose a careful study of antiproton-proton interactions at 75 GeV/c in the Fermilab 30' hybrid bubble chamber. An exposure of 300K pictures is requested to provide 50K interactions of which approximately 7K are annihilation events. Using the properties of this system which is very well matched to the often complex topologies associated with annihilations and to this beam momentum, we plan to study all experimentally accessible features. In particular, single and multi-particle inclusive distributions for charged and neutrals will be measured, exclusive fits will be made where possible, new particles will be searched for, and comparisons made to other energies and to other beam particles.
Date: January 1, 1975
Creator: Jones, M.D.; Jacques, P.; Plano, R.J.; Watts, T.L.; /Rutgers U., Piscataway; Chien, C.Y. et al.
Partner: UNT Libraries Government Documents Department

Photon production at CDF and D0

Description: Prompt photon production has been studied in {bar p}p collisions at {radical}s = 1.8 TeV using the CDF and D0 detectors at Fermilab. The measured inclusive isolated photon spectral at CDF and Do are used to test NLO QCD predictions. The CDF result shows that additional soft radiation (K{sub T}) in excess of NLO QCD is required to explain the data. No new resonance is observed in the photon + jet mass spectrum from D0 which is consistent with NLO QCD predictions. The pseudorapidity distribution of the leading jet in photon events at CDF is compared to different parton distribution sets. The angular distribution is found to be better explained by a larger Bremsstrahlung contribution.
Date: July 1, 1995
Creator: Lamoureux, J.I.
Partner: UNT Libraries Government Documents Department

Search for double parton scattering in the 4 jet channel at D0

Description: We have searched for double parton scattering in the 4-jet channel with an integrated luminosity of 4.4 pb{sup -1}, collected using the D{O} detector during 1994-1995 Fermilab Collider run at a center of mass energy ({radical}s) of 1.8 TeV. We present the preliminary observation of a statistically significant excess of signal.
Date: September 1, 1996
Creator: Yu, Yeonsik
Partner: UNT Libraries Government Documents Department

Search for high mass photon pairs in p{anti p} collisions at {radical}s = 1.8 TeV

Description: The authors present results of a search for diphoton resonances produced inclusively and in association with a vector boson using 100 pb{sup {minus}1} of p{anti p} collisions using the CDF detector. They set upper limits on the product of cross section times branching ratio for p{anti p} {r_arrow} {gamma}{gamma} {r_arrow} X and p{anti p} {r_arrow} {gamma}{gamma} {r_arrow} W/Z. Using a NLO prediction for associated production cross section of a Higgs with a vector boson (W or Z), they set an upper limit on the branching ratio for H {r_arrow} {gamma}{gamma}. They set a lower limit on the mass of a `bosophilic` Higgs boson (e.g. one which couples only to {gamma}, W, and Z bosons with Standard Model couplings) of 82 GeV/c{sup 2} at 95% C.L.
Date: June 29, 1998
Creator: Wilson, P. J.
Partner: UNT Libraries Government Documents Department

Recent D0 results on Z{gamma} production

Description: We report on a new search for anomalous {ital ZV}{sub {gamma}} ({ital V = Z}, {gamma}) couplings in the {ital Z}({ital ee}){gamma} mode with 89 pb{sup -1} of data. The following limits on anomalous coupling parameters were set at 95% CL: {vert_bar}{ital h{sup V}}{sub 10, 30}{vert_bar} {lt} 1.9, {vert_bar}{ital h{sup V}}{sub 20, 40}{vert_bar} {lt} 0.4. We also report on the first measurement of {ital Z(vv)}{gamma} production at hadron colliders using 14 pb{sup - 1} of data. Sensitivity to anomalous couplings in this channel is twice as good as that for the combined electron and muon channel analysis reported earlier. We set the following 95% CL limits on the {ital ZV}{gamma} couplings: {vert_bar}{ital h{sup V}}{sub 10, 30}{vert_bar} {lt} 0.9, {vert_bar}{ital h{sup V}}{sub 20, 40}{vert_bar} {lt} 0.2 which are the tightest available at the present time.
Date: November 1996
Creator: Landsberg, G.
Partner: UNT Libraries Government Documents Department

W`, Z`, leptoquarks and bump hunting at the Tevatron

Description: This paper summarizes recent results on non-SUSY searches at the Fermilab Tevatron p{bar p} collider. All the analysis are based on the complete data samples recorded by both the CDF and D0 collaborations during the 1992-1995 running period (Run 1), and correspond to {approx} 100 pb{sup -1}. Searches for new neutral heavy vector bosons, leptoquarks, dijet mass resonances, and associated production of new heavy scalars together with vector bosons show no evidence for new physics. Consequently, the results have been interpreted in terms of 95% confidence level limits on production cross sections and new particle masses.
Date: May 1, 1997
Creator: Valls, J.A. & Collaboration, The CDF and DO
Partner: UNT Libraries Government Documents Department