Dr Elizabeth Gallas

Abstract:

The distribution of the transverse energy in jets has been measured in pp collisions at s=1.8 TeV TeV using the DØ detector at Fermilab. This measurement of the jet shape is made as a function of jet transverse energy in both the central and forward rapidity regions. Jets are shown to narrow both with increasing transverse energy and with increasing rapidity. Next-to-leading order partonic QCD calculations are compared to the data. Although the calculations qualitatively describe the data, they are shown to be very dependent on renormalization scale, parton clustering algorithm, and jet direction definition and they fail to describe the data in all regions consistently. © 1995.

Abstract:

We report a measurement of the inclusive muon and b-quark production cross sections in pp» collisions at s=1.8 TeV using the D0 detector at the Fermilab Tevatron collider. The inclusive muon spectrum extends over the kinematic range | y|<0.8 and 3.56GeV/c is extracted, and agrees with next-to-leading order QCD predictions within the experimental and theoretical uncertainties. © 1995 The American Physical Society.

Abstract:

We performed a direct search for the anomalous ZZ and Z couplings by studying pp» +X (=e,) events at s=1.8 TeV with the D0 detector at the Fermilab Tevatron Collider. A fit to the transverse energy spectrum of the photon in the signal events, based on the data set corresponding to an integrated luminosity of 14.3 pb-1 (13.7 pb-1) for the electron (muon) channel, yields the following 95% confidence level limits on the anomalous CP-conserving ZZ couplings: |h30Z|<1.8 (h40Z=0) and |h40Z|<0.5 (h30Z=0), for a form-factor scale =500 GeV. Limits for the Z couplings and CP-violating couplings are also discussed. © 1995 The American Physical Society.

Abstract:

The WW gauge boson couplings were measured using pp» +X (=e,) events at s=1.8 TeV observed with the D0 detector at the Fermilab Tevatron Collider. The signal, obtained from the data corresponding to an integrated luminosity of 13.8 pb-1, agrees well with the standard model prediction. A fit to the photon transverse energy spectrum yields limits at the 95% confidence level on the CP-conserving anomalous coupling parameters of -1.6< <1.8 (=0) and -0.6< <0.6 (=0). Similar limits are obtained for the CP-violating coupling parameters. © 1995 The American Physical Society.

Abstract:

The D0 Collaboration reports on a search for the standard model top quark in pp̄ collisions at s=1.8TeV at the Fermilab Tevatron with an integrated luminosity of approximately 50 pb-1. We have searched for tt̄ production in the dilepton and single-lepton decay channels with and without tagging of b-quark jets. We observed 17 events with an expected background of 3.8±0.6 events. The probability for an upward fluctuation of the background to produce the observed signal is 2×10-6 (equivalent to 4.6 standard deviations). The kinematic properties of the excess events are consistent with top quark decay. We conclude that we have observed the top quark and measured its mass to be 199-21+19 (stat) ±22 (syst) GeV/c2 and its production cross section to be 6.4±2.2 pb. © 1995 The American Physical Society.