The Charge Asymmetry in W-Boson Decays Produced in p-pbar Collisions at sqrt(s) = 1.8 TeV

TL;DR

This paper reports a measurement of charge asymmetry in W-boson decays from proton-antiproton collisions at 1.8 TeV, providing insights into quark distribution ratios at low x, and favoring certain parton distribution models.

Contribution

It presents the first detailed measurement of W-boson charge asymmetry at Tevatron energies, constraining the d/u quark distribution ratio more effectively than previous methods.

Findings

MRS parton distributions are favored over CTEQ sets.

W asymmetry data better constrains d/u ratio than F2 measurements.

Results support specific models of quark distributions at low x.

Abstract

The charge asymmetry has been measured using $19,039~W$ decays recorded by the CDF detector during the 1992-93 run of the Tevatron Collider. The asymmetry is sensitive to the ratio of $d$ and $u$ quark distributions to $x<0.01$ at $Q^2 \approx M_W^2$, where nonperturbative effects are minimal. It is found that of the two current sets of parton distributions, those of Martin, Roberts and Stirling (MRS) are favored over the sets most recently produced by the CTEQ collaboration. The $W$ asymmetry data provide a stronger constraints on $d/u$ ratio than the recent measurements of $F_2^{\mu n}/F_2^{\mu p}$ which are limited by uncertainties originating from deutron corrections.