Direct Measurement of the $W$ Production Charge Asymmetry in $\ppbar$ Collisions at $\sqrt{s} = 1.96$ TeV

TL;DR

This paper reports the first direct measurement of the $W$ boson charge asymmetry as a function of rapidity in proton-antiproton collisions at 1.96 TeV, providing new insights into quark momentum distributions.

Contribution

It introduces a novel direct measurement method of $W$ charge asymmetry as a function of $W$ rapidity in $ar{p}p$ collisions, improving constraints on parton distribution functions.

Findings

Measured asymmetry in $| ext{y}_W| < 3.0$ region.

Provides more direct constraints on up/down quark ratios.

Uses 1 fb$^{-1}$ of data from CDF II detector.

Abstract

We present the first direct measurement of the $W$ production charge asymmetry as a function of the $W$ boson rapidity $\yW$ in $\ppbar$ collisions at $\sqrt{s} = 1.96$ $\TeV$. We use a sample of $\wenu$ events in data from 1 $\ifb$ of integrated luminosity collected using the CDF II detector. In the region $|\yW| <$ 3.0, this measurement is capable of constraining the ratio of up and down quark momentum distributions in the proton more directly than in previous measurements of the asymmetry that are a function of the charged-lepton pseudorapidity.