# DIS 2015 - XXIII. International Workshop on Deep-Inelastic Scattering and Related Subjects

27 April 2015 to 1 May 2015
US/Central timezone

## Constraining Sea Quark Distributions Through $W^{\pm}$ Cross Section Ratios Measured at STAR

29 Apr 2015, 11:35
25m
FORUM ()

### FORUM

WG1 Structure Functions and Parton Densities

### Speaker

Dr Matthew Posik (Temple University)

### Description

Over the past several years the STAR experiment at RHIC has been contributing to our understanding of the proton structure. Through proton-proton collisions, STAR is well equipped to measure the e$^{\pm}$ leptonic decays of $W^{\pm}$ bosons in the mid-rapidity region (-1.1 $\le \eta \le$ 1.1) at $\sqrt{s}$ = 500/510 GeV. The $W$ cross section ratio ($W^+/W^-$) is sensitive to unpolarized $u$, $d$, $\bar{u}$, and $\bar{d}$ quark distributions. At these kinematics STAR is able to measure the quark distributions near Bjorken-x of 0.1. The RHIC runs in 2012 and 2013 at $\sqrt{s}$ = 500/510 GeV saw a significant increase in delivered luminosity from previous years. This resulted in using data samples of about 80 and 250 pb$^{-1}$ of integrated luminosity, respectively. The increased statistics will lead to a higher precision measurement of the $W^{+}/W^{-}$ cross section ratio as well as its $\eta$ dependence at mid-rapidity. Presented here is an update of the $W$ cross section ratio analysis from the STAR 2012 and 2013 runs.

### Primary author

Dr Matthew Posik (Temple University)

 Slides