Dr Elizabeth Gallas

Abstract:

The cross section for the inclusive production of isolated photons has been measured in p over(p, ̄) collisions at sqrt(s) = 1.96   TeV with the DØ detector at the Fermilab Tevatron Collider. The photons span transverse momenta 23 to 300 GeV and have pseudorapidity | η | < 0.9. The cross section is compared with the results from two next-to-leading order perturbative QCD calculations. The theoretical predictions agree with the measurement within uncertainties. © 2006 Elsevier B.V. All rights reserved.

Abstract:

We have searched for a heavy resonance decaying into a Z+jet final state in pp̄ collisions at a center of mass energy of 1.96TeV at the Fermilab Tevatron collider using the D0 detector. No indication for such a resonance was found in a data sample corresponding to an integrated luminosity of 370pb-1. We set upper limits on the cross section times branching fraction for heavy resonance production at the 95% C.L. as a function of the resonance mass and width. The limits are interpreted within the framework of a specific model of excited quark production. © 2006 The American Physical Society.

Abstract:

A search for gaugino pair production with a trilepton signature in the framework of R-parity violating supersymmetry via the couplings λ121, λ122, or λ133 is presented. The data, corresponding to an integrated luminosity of L ≈ 360  pb-1, were collected from April 2002 to August 2004 with the D∅ detector at the Fermilab Tevatron Collider, at a center-of-mass energy of sqrt(s) = 1.96  TeV. This analysis considers final states with three charged leptons with the flavor combinations eeℓ, μμℓ, and eeτ (ℓ = e or μ). No evidence for supersymmetry is found and limits at the 95% confidence level are set on the gaugino pair production cross section and lower bounds on the masses of the lightest neutralino and chargino are derived in two supersymmetric models. © 2006 Elsevier B.V. All rights reserved.

Abstract:

We report results of a study of the B(s)(0) oscillation frequency using a large sample of B(s)(0) semileptonic decays corresponding to approximately 1 fb(-1) of integrated luminosity collected by the D0 experiment at the Fermilab Tevatron Collider in 2002-2006. The amplitude method gives a lower limit on the B(s)(0) oscillation frequency at 14.8 ps(-1) at the 95% C.L. At delta m(s) = 19 ps(-1), the amplitude deviates from the hypothesis A= 0(1) by 2.5 (1.6) standard deviations, corresponding to a two-sided C.L. of 1% (10%). A likelihood scan over the oscillation frequency, delta m(s), gives a most probable value of 19 ps(-1) and a range of 17 < delta m(s) < 21 ps(-1)at the 90% C.L., assuming Gaussian uncertainties. This is the first direct two-sided bound measured by a single experiment. If delta m(s) lies above 22 ps(-1), then the probability that it would produce a likelihood minimum similar to the one observed in the interval 16-22 ps(-1) is (5.0 +/- 0.3)%.

Abstract:

The results of a search for squarks and gluinos using data from p over(p, ̄) collisions recorded at a center-of-mass energy of 1.96 TeV by the DØ detector at the Fermilab Tevatron Collider are reported. The topologies analyzed consist of acoplanar-jet and multijet events with large missing transverse energy. No evidence for the production of squarks or gluinos was found in a data sample of 310 pb-1. Lower limits of 325 and 241 GeV were derived at the 95% C.L. on the squark and gluino masses, respectively, within the framework of minimal supergravity with tan β = 3, A0 = 0, and μ < 0. © 2006 Elsevier B.V. All rights reserved.