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A Search for supersymmetric Higgs bosons in the di-tau decay mode in p anti-p collisions at s**(1/2) = 1.8-TeV

Description: A search for direct production of Higgs bosons in the di-tau decay mode is performed with 86.3 {+-} 3.5 pb{sup -1} of data collected with the Collider Detector at Fermilab during the 1994-1995 data taking period of the Tevatron. We search for events where one tau decays to an electron plus neutrinos and the other tau decays hadronically. We perform a counting experiment and set limits on the cross section for supersymmetric Higgs boson production where tan {beta} is large and m{sub A} is small. For a benchmark parameter space point where m{sub A{sup 0}} = 100 GeV/c{sup 2} and tan {beta} = 50, we limit the production cross section multiplied by the branching ratio to be less than 77.9 pb at the 95% confidence level compared to theoretically predicted value of 11.0 pb. This is the first search for Higgs bosons decaying to tau pairs at a hadron collider.
Date: June 1, 2005
Creator: Acosta, D.; Affolder, Anthony A.; Albrow, M. G.; Ambrose, D.; Amidei, D.; Anikeev, K. et al.
Partner: UNT Libraries Government Documents Department

Measurement of the W boson polarization in top decay at CDF at s**(1/2) = 1.8-TeV

Description: The polarization of the W boson in t {yields} Wb decay is unambiguously predicted by the Standard Model of electroweak interactions and is a powerful test of our understanding of the tbW vertex. We measure this polarization from the invariant mass of the b quark from t {yields} Wb and the lepton from W {yields} {ell}{nu} whose momenta measure the W decay angle and direction of motion, respectively. In this paper we present a measurement of the decay rate (f{sub V + A}) of the W produced from the decay of the top quark in the hypothesis of V + A structure of the tWb vertex. We find no evidence for the non-standard V + A vertex and set a limit on f{sub V + A} < 0.80 at 95% confidence level. By combining this result with a complementary observable in the same data, we assign a limit on f{sub V + A} < 0.61 at 95% CL. This corresponds to a constraint on the right-handed helicity component of the W polarization of f{sub +} < 0.18 at 95% CL. This limit is the first significant direct constraint on f{sub V + A} in top decay.
Date: November 1, 2004
Creator: Acosta, D.; Affolder, Anthony A.; Albrow, M. G.; Ambrose, D.; Amidei, D.; Anikeev, K. et al.
Partner: UNT Libraries Government Documents Department

Measurement of the azimuthal angle distribution of leptons from W boson decays as a function of the W transverse momentum in p anti-p collisions at s**(1/2) = 1.8-TeV

Description: We present the first measurement of the A{sub 2} and A{sub 3} angular coefficients of the W boson produced in proton-antiproton collisions. We study W {yields} ev{sub e} and W {yields} {mu}{nu}{sub {mu}} candidate events produced in association with at least one jet at CDF, during Run Ia and Run Ib of the Tevatron at {radical}s = 1.8 TeV. The corresponding integrated luminosity was 110 pb{sup -1}. The jet balances the transverse momentum of the W and introduces QCD effects in W boson production. The extraction of the angular coefficients is achieved through the direct measurement of the azimuthal angle of the charged lepton in the Collins-Soper rest-frame of the W boson. The angular coefficients are measured as a function of the transverse momentum of the W boson. The electron, muon, and combined results are in good agreement with the Standard Model prediction, up to order {alpha}{sub s}{sup 2} in QCD.
Date: April 1, 2005
Creator: Acosta, D.; Affolder, Anthony A.; Albrow, M. G.; Ambrose, D.; Amidei, D.; Anikeev, K. et al.
Partner: UNT Libraries Government Documents Department

Measurement of the cross section for t anti-t production in p anti-p collisions using the kinematics of lepton + jets events

Description: The authors present a measurement of the top pair production cross section in p{bar p} collisions at {radical}s = 1.96 TeV. We collect a data sample with an integrated luminosity of 194 {+-} 11 pb{sup -1} with the CDF II detector at the Fermilab Tevatron. We use an artificial neural network technique to discriminate between top pair production and background processes in a sample of 519 lepton + jets events, which have one isolated energetic charged lepton, large missing transverse energy and at least three energetic jets. We measure the top pair production cross section to be {sigma}{sub t{bar t}} = 6.6 {+-} 1.1 {+-} 1.5 pb, where the first uncertainty is statistical and the second is systematic.
Date: April 1, 2005
Creator: Acosta, D.; Adelman, J.; Affolder, Anthony A.; Akimoto, T.; Albrow, M. G.; Ambrose, D. et al.
Partner: UNT Libraries Government Documents Department

Measurement of the J/psi meson and b-hadron production cross sections in p anti-p collisions at s(NN)**(1/2) = 1960-GeV

Description: We present a new measurement of the inclusive and differential production cross sections of J/{psi} mesons and b-hadrons in proton-antiproton collisions at {radical}s = 1960 GeV. The data correspond to an integrated luminosity of 39.7 pb{sup -1} collected by the CDF Run II detector. We find the integrated cross section for inclusive J/{psi} production for all transverse momenta from 0 to 20 GeV/c in the rapidity range |y| < 0.6 to be 4.08 {+-} 0.02(stat){sub -0.33}{sup +0.36}(syst) {mu}b. We separate the fraction of J/{psi} events from the decay of the long-lived b-hadrons using the lifetime distribution in all events with p{sub T} (J/{psi}) > 1.25 GeV/c. We find the total cross section for b-hadrons, including both hadrons and anti-hadrons, decaying to J/{psi} with transverse momenta greater than 1.25 GeV/c in the rapidity range |y(J/{psi})| < 0.6, is 0.330 {+-} 0.005(stat){sub -0.033}{sup +0.036}(syst) {mu}b. Using a Monte Carlo simulation of the decay kinematics of b-hadrons to all final states containing a J/{psi}, we extract the first measurement of the total single b-hadron cross section down to zero transverse momentum at {radical}s = 1960 GeV. We find the total single b-hadron cross section integrated over all transverse momenta for b-hadrons in the rapidity range |y| < 0.6 to be 17.6 {+-} 0.4(stat){sub -2.3}{sup +2.5}(syst) {mu}b.
Date: December 1, 2004
Creator: Acosta, D.; Adelman, J.; Affolder, T.; Akimoto, T.; Albrow, M. G.; Ambrose, D. et al.
Partner: UNT Libraries Government Documents Department

K0(s) and Lambda0 production studies in p anti-p collisions at s**(1/2) = 1800 and 630-GeV

Description: The authors present a study of the production of K{sub s}{sup 0} and {Lambda}{sup 0} in inelastic p{bar p} collisions at {radical}s = 1800 and 630 GeV using data collected by the CDF experiment at the Fermilab Tevatron. Analyses of K{sub s}{sup 0} and {Lambda}{sup 0} multiplicity and transverse momentum distributions, as well as of the dependencies of the average number and (p{sub T}) of K{sub s}{sup 0} and {Lambda}{sup 0} on charged particle multiplicity are reported. Systematic comparisons are performed for the full sample of inelastic collisions, and for the low and high momentum transfer subsamples, at the two energies. The p{sub T} distributions extend above 8 GeV/c, showing a (p{sub T}) higher than previous measurements. The dependence of the mean K{sub s}{sup 0}({Lambda}{sup 0}) p{sub T} on the charged particle multiplicity for the three samples shows a behavior analogous to that of charged primary tracks.
Date: April 1, 2005
Creator: Acosta, D.; Affolder, Anthony A.; Albrow, M. G.; Ambrose, D.; Amidei, D.; Anikeev, K. et al.
Partner: UNT Libraries Government Documents Department

Measurement of charged particle multiplicities in gluon and quark jets in proton anti-proton collisions at s**(1/2) = 1.8-TeV

Description: The authors report the first model independent measurement of charged particle multiplicities in quark and gluon jets, N{sub q} and N{sub g}, produced at the Tevatron in p{bar p} collisions with center-of-mass energy 1.8 TeV and recorded by the Collider Detector at Fermilab. The measurements are made for jets with average energies 41 and 53 GeV by counting charged particle tracks in cones with opening angle of {theta}{sub c} = 0.28, 0.36, and 0.47 rad around the jet axis. The corresponding jet hardness Q = E{sub jet}{theta}{sub c} varies in the range from 12 GeV to 25 GeV. At Q = 19 GeV, the ratio of multiplicities r = N{sub g}/N{sub q} is found to be 1.64 {+-} 0.17, where statistical and systematic uncertainties are added in quadrature. The results are in agreement with re-summed perturbative QCD calculations.
Date: July 1, 2004
Creator: Acosta, D.; Affolder, Anthony A.; Albrow, M. G.; Ambrose, D.; Amidei, D.; Anikeev, K. et al.
Partner: UNT Libraries Government Documents Department

Inclusive charged hadron and K sup 0 production in two-photon interactions

Description: The analogous process to quark pair production in e{sup +} e{sup {minus}} annihilation is the hard-scattering quark exchange process in {gamma}{gamma} interactions. This hard-scattering process is expected to dominate the cross section at high transverse momenta of the produced quarks. Experimentally, one has looked for this process in two-jet as well as inclusive particle production and has found a relatively low PT onset of hard scattering in {gamma}{gamma} interactions. This report examines the issue in more detail (high statistics) for charged particle inclusive production and checks if the heavier flavors display a similar behavior in inclusive K{sup 0} production.
Date: March 1, 1988
Creator: Cords, D.; Boyer, J.; Butler, F.; Gidal, G.; Abrams, G. S.; Amidei, D. et al.
Partner: UNT Libraries Government Documents Department

Operation of the CDF Silicon Vertex Detector with colliding beams at Fermilab

Description: In this paper we briefly describe the main features of the CDF Silicon Vertex Detector (SVX) and discuss its performance during actual colliding beam operation at the Fermilab Tevatron. Details on S/N ratio, alignment, resolution and efficiency are given.
Date: October 1, 1992
Creator: Bedeschi, F.; Bolognesi, V.; Dell`Agnello, S.; Galeotti, S.; Grieco, G.; Mariotti, M. et al.
Partner: UNT Libraries Government Documents Department

Inclusive charged hadron and K{sup 0} production in two-photon interactions

Description: The analogous process to quark pair production in e{sup +} e{sup {minus}} annihilation is the hard-scattering quark exchange process in {gamma}{gamma} interactions. This hard-scattering process is expected to dominate the cross section at high transverse momenta of the produced quarks. Experimentally, one has looked for this process in two-jet as well as inclusive particle production and has found a relatively low PT onset of hard scattering in {gamma}{gamma} interactions. This report examines the issue in more detail (high statistics) for charged particle inclusive production and checks if the heavier flavors display a similar behavior in inclusive K{sup 0} production.
Date: March 1, 1988
Creator: Cords, D.; Boyer, J.; Butler, F.; Gidal, G.; Abrams, G. S.; Amidei, D. et al.
Partner: UNT Libraries Government Documents Department

An integral field spectrograph for SNAP supernova studies

Description: A well-adapted spectrograph concept has been developed for the SNAP (SuperNova/Acceleration Probe) experiment. The goal is to ensure proper identification of Type Ia supernovae and to standardize the magnitude of each candidate by determining explosion parameters. An instrument based on an integral field method with the powerful concept of imager slicing has been designed and is presented in this paper. The spectrograph concept is optimized to have very high efficiency and low spectral resolution (R {approx} 100), constant through the wavelength range (0.35-1.7{micro}m), adapted to the scientific goals of the mission.
Date: July 29, 2002
Creator: Ealet, Anne; Prieto, E.; Bonissent, A.; Malina, R.; Basa, S.; LeFevre, O. et al.
Partner: UNT Libraries Government Documents Department

Search for New Bottomlike Quark Pair Decays Q Q-Bar to (T W- ) (T-Bar W -) in Same-Charge Dilepton Events

Description: We report the most restrictive direct limits on masses of fourth-generation down-type quarks b{prime}, and quark-like composite fermions (B or T{sub 5/3}), decaying promptly to tW{sup {-+}}. We search for a significant excess of events with two same-charge leptons (e, {mu}), several hadronic jets, and missing transverse energy. An analysis of data from p{bar p} collisions with an integrated luminosity of 2.7 fb{sup -1} collected with the CDF II detector at Fermilab yields no evidence for such a signal, setting mass limits m{sub b{prime}}, m{sub B} > 338 GeV/c{sup 2} and m{sub T{sub 5/3}} > 365 GeV/c{sup 2} at 95% confidence level.
Date: April 2, 2012
Creator: Aaltonen, T.; Phys., /Helsinki Inst. of; Adelman, J.; /Chicago U., EFI; Alvarez Gonzalez, B.; Phys., /Cantabria Inst. of et al.
Partner: UNT Libraries Government Documents Department

Exotic Physics: Search for New Physics Leading to High Mass Tau Pairs With ppbar Collisions at 1.96 TeV Using Cdf Ii

Description: Abstract: We present the results of a search for anomalous resonant production of tau lepton pairs with large invariant mass, the first such search using the CDF II Detector in Run II of the Tevatron p{bar p} collider. Such anomalous production could arise from various new physics processes. In a data sample corresponding to 195 pb{sup -1} of integrated luminosity we predict 2.8 {+-} 0.5 events from Standard Model background processes and observe 4. We use this result to set limits on the production of heavy scalar and vector particles decaying to tau lepton pairs.
Date: June 15, 2005
Creator: Academia Sinica Institute of Physics
Partner: UNT Libraries Government Documents Department