Weak-boson production at Fermilab Tevatron energies

Weak bosons are produced in hadron collisions by quarks and antiquarks withaverage fractional momenta /ital x/=/ital M//sub /ital W/,/ital Z/// /radical/s . When /radical//ital s/is increased by a factor of 3, the average value of /ital x/ shifts fromabout 0.15 at CERN /ital pp/bar // collider energies to 0.05 at the FermilabTevatron, i.e., from a regime where valence quarks dominate to a regime wheresea quarks dominate the production features of weak bosons. We investigatesystematically the problem of calculating /ital W/ and /ital Z/ cross sections inthis new regime, paying special attention to the ratio/sigma/(/ital W/)//sigma/(/ital Z/) which is necessary for determining the ratio oftotal widths /Gamma/(/ital W/)//Gamma/(/ital Z/) from hadron-collider data. Weemphasize that with the increased statistics in /ital pp/bar // experiments, theparton fluxes responsible for the production of weak bosons can be controlledinternally by a study of the asymmetry of the rapidity distribution of the/ital W/ boson. We derive a relation between the asymmetry in /ital W//sup /plus minus//rapidity distributions and the ratio/ital F//sub 2//sup /ital n///F/sub 2//sup p/ of deep-inelastic lepton-hadronscattering structure functions. The production rates of weak bosons also becomesensitive to production via the charm quark. This calculation raises someinteresting theoretical issues. We discuss both problems in detail. We alsostudy the implications of our results for the determination of the number oflight neutrinos and the mass of the top quark via a measurement of the/ital W/-to-/ital Z/ event ratio.