Dr Elizabeth Gallas

Abstract:

We present a measurement of the Drell-Yan cross section at high dielectron invariant mass using 120 pb-1 of data collected in pp collisions at √ s = 1.8 TeV by the D0 Collaboration during 1992-1996. No deviation from standard model expectations is observed. We use the data to set limits on the quark-electron compositeness scale. The 95% confidence level lower limits on the compositeness scale vary between 3.3 and 6.1 TeV depending on the assumed form of the effective contact interaction. © 1999 The American Physical Society.

Abstract:

We present a measurement of t¯t production in p¯p collisions at √s = 1.8TeV from 110pb-1 of data collected in the all-jets decay channel with the D0 detector at Fermilab. A neural network analysis yields a cross section of 7.1 ± 2.8(stat) ± 1.5(syst)pb at a top quark mass (mt) of 172.1GeV/c2. Using previous D0 measurements from dilepton and single lepton channels, the combined D0 result for the t¯t production cross section is 5.9 ± 1.2(stat) ± 1.1(syst)pb for mt = 172.1GeV/c2. © 1999 The American Physical Society.

Abstract:

We report a measurement of the top quark mass using six candidate events for the process (Formula presented), observed in the D0 experiment at the Fermilab (Formula presented) collider. Using maximum likelihood fits to the dynamics of the decays, we measure a mass for the top quark of (Formula presented). We combine this result with our previous measurement in the (Formula presented) channel to obtain (Formula presented) as the best value of the mass of the top quark measured by D0. © 1999 The American Physical Society.

Abstract:

We present a search for charged Higgs bosons in decays of pair-produced top quarks using 109.2 ± 5.8pb-1 of data recorded from pp collisions at √ s = 1.8 TeV by the D0 detector during 1992-1996 at the Fermilab Tevatron. No evidence is found for charged Higgs production, and most parts of the [MH+, tan β] parameter space where the decay t → H+ b has a branching fraction close to or larger than that for t → W+ b are excluded at 95% confidence level. Assuming mt = 175 GeV and σ(pp → tt) = 5.5 pb, for MH+ = 60 GeV, we exclude tan β < 0.97 and tan β > 40.9. © 1999 The American Physical Society.

Abstract:

We report on a search for second generation leptoquarks (LQ) produced in pp collisions at √ = 1.8TeV using the D0 detector at Fermilab. Second generation leptoquarks are assumed to be produced in pairs and to decay to either μ or v and either a strange or a charm quark (q). Limits are placed on σ (pp → LQLQ → μ v + jets) as a function of the mass of the leptoquark. For equal branching ratios to μq and vq second generation scalar leptoquarks with a mass below 160 GeV/c2 vector leptoquarks with anomalous minimal vector couplings with a mass below 240 GeV/c2 and vector leptoquarks with Yang-Mills couplings with a mass below 290 GeV/c2 are excluded at the 95% confidence level. © 1999 The American Physical Society.