Tests of Qcd in W and Z Production at Tevatron the Inclusive Production Cross Sections 9]

We present measurements of the production cross sections times leptonic branching fractions and the transverse momentum distributions of W and Z bosons in p p collisions at p s = 1:8 TeV using data collected with the DD detector at the Fermilab Tevatron p p collider. A preliminary measurement of the W charge asymmetry is also presented. At p s = 1:8 TeV, production of W and Z bosons in p p collisions proceeds primarily via q q annihilation accompanied by an initial state gluon radiation which produces the transverse momentum, p T , of W and Z bosons. Absolute predictions for the inclusive production cross sections, W and Z , have been calculated to order 2 s by van Neerven et al. 1]. In the low p T region (p W T ; p Z T < 20 GeV=c) multiple soft gluon emission is expected to dominate the initial state radiation and the diierential cross section, dd=dp T , has been calculated using a soft gluon resummation technique 2{6]. In the high p T region (p W T ; p Z T > 20 GeV=c) perturbative QCD calculations are expected to describe the dd=dp T 7]. Thus measurements of the inclusive and diierential cross sections of W and Z production provide tests of QCD. Experimentally, use of leptonic decays of W and Z bosons, which do not involve nal state strong interactions, allows for high precision measurements of their inclusive processes. In this report we present measurements of the production cross sections times leptonic 5 branching fractions and the p T distributions of W and Z bosons using data collected with the DD detector 8] in the 1992{1993 run at the Fermilab Tevatron p p collider at p s = 1:8 TeV. We present preliminary results using a partial data sample from the 1994{1995 run. We also present a preliminary measurement of the W charge asymmetry using W ! sample, from which the information on parton distribution function (pdf) can be extracted. (1) where N obs is the number of observed events, N bkgd is the number of expected background events, A W is the kinematic and geometric acceptance, W is the detection eeciency, and L is the integrated luminosity used in the analysis. The Z boson cross section, Z B(Z ! ll), is calculated in a similar fashion. Electrons were detected in hermetic, uranium liquid-argon calorimeters with an …