Dr Elizabeth Gallas

Abstract:

A search for leptoquarks has been performed in 310 pb -1 of data from p over(p, ̄) collisions at a center-of-mass energy of 1.96 TeV, collected by the D0 detector at the Fermilab Tevatron Collider. The topology analyzed consists of acoplanar jets with missing transverse energy. The data show good agreement with standard model expectations, and a lower mass limit of 136 GeV has been set at the 95% C.L. for a scalar leptoquark decaying exclusively into a quark and a neutrino. © 2006 Elsevier B.V. All rights reserved.

Abstract:

Limits are set on anomalous WWγ and WWZ trilinear gauge couplings using W+W-→e+νee-ν̄e, W+W-→e±νeμ νμ, and W+W-→μ+νμμ-ν̄μ events. The data set was collected by the Run II D0 detector at the Fermilab Tevatron Collider and corresponds to approximately 250pb-1 of integrated luminosity at s=1.96TeV. Under the assumption that the WWγ couplings are equal to the WWZ couplings and using a form factor scale of Λ=2.0TeV, the combined 95% C.L. one-dimensional coupling limits from all three channels are -0.32<Δκ<0.45 and -0.29<λ<0.30. © 2006 The American Physical Society.

Abstract:

We present a search for supersymmetry in the R-parity violating resonant production and decay of smuons and muon sneutrinos in the channels mu-->chi(1)(0)mu, mu-->chi(2,3,4)(0)mu, and nu(mu)-->chi(1,2)(+/-)mu. We analyzed 0.38 fb(-1) of integrated luminosity collected between April 2002 and August 2004 with the D0 detector at the Fermilab Tevatron Collider. The observed number of events is in agreement with the standard model expectation, and we calculate 95% C.L. limits on the slepton production cross section times branching fraction to gaugino plus muon, as a function of slepton and gaugino masses. In the framework of minimal supergravity, we set limits on the coupling parameter lambda(211)('), extending significantly previous results obtained in Run I of the Tevatron and at the CERN LEP collider.

Abstract:

The DØ experiment enjoyed a very successful data-collection run at the Fermilab Tevatron collider between 1992 and 1996. Since then, the detector has been upgraded to take advantage of improvements to the Tevatron and to enhance its physics capabilities. We describe the new elements of the detector, including the silicon microstrip tracker, central fiber tracker, solenoidal magnet, preshower detectors, forward muon detector, and forward proton detector. The uranium/liquid-argon calorimeters and central muon detector, remaining from Run I, are discussed briefly. We also present the associated electronics, triggering, and data acquisition systems, along with the design and implementation of software specific to DØ. © 2006 Elsevier B.V. All rights reserved.

Abstract:

We present the measurement of R = B (t → W b) / B (t → W q) in p over(p, ̄) collisions at sqrt(s) = 1.96 TeV, using 230 pb-1 of data collected by the DØ experiment at the Fermilab Tevatron Collider. We fit simultaneously R and the number (Nt over(t, ̄)) of selected top quark pairs (t over(t, ̄)), to the number of identified b-quark jets in events with one electron or one muon, three or more jets, and high transverse energy imbalance. To improve sensitivity, kinematical properties of events with no identified b-quark jets are included in the fit. We measure R = 1.03-0.17+0.19 (stat + syst), in good agreement with the standard model. We set lower limits of R > 0.61 and | Vt b | > 0.78 at 95% confidence level. © 2006 Elsevier B.V. All rights reserved.