D0 Findings on the Top Quark

TL;DR

This paper reports recent measurements of the top quark mass and production cross section from the D0 experiment, including combined results with CDF, and presents preliminary searches for charged Higgs production in top decays.

Contribution

It provides updated measurements of top quark properties and combines results from multiple channels and experiments, also exploring potential charged Higgs signals in top decays.

Findings

Top quark mass measured as 172.1 +/- 7.1 GeV/c^2.

t-tbar production cross section found to be 5.9 +/- 1.7 pb.

Combined analysis yields sigma(t-tbar) = 6.7 +/- 1.3 pb at m(top) = 173.8 +/- 5.2 GeV/c^2.

Abstract

Recent results on top quark physics with the D0 experiment in pbar-p collisions at sqrt(s) = 1.8 TeV for an integrated luminosity of 125 pb**-1 are reported. The direct measurement of the top quark mass uses single lepton and dilepton events, giving the result m(top) = 172.1 +/- 7.1 GeV/c**2. The measurement of the t-tbar production cross section includes analyses from 9 top decay channels: dilepton (t-tbar --> e+mu, e+e, and mu+mu), electron and neutrino (t-tbar --> e+nu), single leptons (t-tbar --> e + jets, t-tbar --> mu + jets) with and without b tagging, and all-jets (t-tbar --> 6 jets). We measure the t-tbar production cross section to be 5.9 +/- 1.7 pb at m(top) = 172.1 GeV/c**2. Combining the D0 and the CDF measurements of the top quark mass and combining their t-tbar cross sections, in both cases taking into account error correlations, yields unofficially sigma(t-tbar) = 6.7 +/- 1.3 pb at an averaged top quark mass of m(top) = 173.8 +/- 5.2 GeV/c**2. Preliminary results on a search for charged Higgs production in top events, t --> Higgs + b, are presented.