Speaker
Description
While the unpolarized valence quark ($d$ and $u$) distributions are well determined from DIS and $pp/p\bar{p}$ experiments, their sea (anti-)quark counterparts, $\bar{d}$ and $\bar{u}$, are much less constrained, in particular, near the valence region (momentum fraction, $x \sim 0.2$).
Measurements of $W^+$ and $W^-$ production in $pp$ collider experiments can be used to probe the $\bar{d}$ and $\bar{u}$ at a large $Q^2$ set by the $W$ mass.
Presented in this talk are the latest updates of $W^+$ and $W^-$ cross sections and their ratio using the STAR $pp$ collision data at the center-of-mass energy of $\sqrt{s} = 510\,\mathrm{GeV}$ collected in 2017, corresponding to an integrated luminosity of $350\,\mathrm{pb^{-1}}$.
The measurements were performed by tagging leptons from the weak decay channel ($W \rightarrow e\nu$) arising from the mid $(|\eta|<1)$ and intermediate rapidities $(1 < \eta < 1.5)$, probing the $\bar{d}$ and $\bar{u}$ within the proton momentum fraction range of $0.06 < x < 0.4$.
These measurements will improve the precision of the previous measurements performed with the STAR 2011, 2012, and 2013 data.
A status update for the STAR 2022 $pp \;\sqrt{s} = 510 \;\textrm{GeV}$ dataset will be presented.
| Speaker confirmation | Yes |
|---|