Flavor Asymmetry of the Nucleon Sea and W Boson Production

TL;DR

This paper explores how W-boson production in proton-proton collisions can be used to measure the flavor asymmetry between anti-up and anti-down quarks in the proton's sea, providing a new method free from certain systematic effects.

Contribution

It demonstrates the sensitivity of W-boson production ratios to sea-quark flavor asymmetry and assesses the feasibility of measuring these ratios at RHIC and LHC.

Findings

W^+ and W^- production ratios are sensitive to / quark ratios.

Ratios are unaffected by charge-symmetry-breaking and nuclear-binding effects.

Feasibility of measurements at RHIC and LHC is confirmed.

Abstract

The advantage and feasibility of using $W$-boson production to extract unique information on the flavor asymmetry of the $\bar u$ and $\bar d$ sea-quark distributions in the proton are examined. The $W^+$ and $W^-$ production cross section ratios in $p+p$ collisions are shown to be sensitive to the $\bar d/ \bar u$ ratios, and they are free from charge-symmetry-breaking and nuclear-binding effects. The feasibility for measuring these ratios at the RHIC and LHC proton-proton colliders, as well as the expected sensitivity to the $\bar d/ \bar u$ ratios, are also presented.