Speaker
Description
While the unpolarized valence quark ($d$ and $u$) distributions are well determined from DIS experiments, their sea quark counterparts, $\bar{d}$ and $\bar{u}$, are much less constrained, in particular, near the valence region.
Measurements of $W^+/W^-$ production ratio in $pp$ collider experiments, such as the STAR experiment at RHIC, are sensitive to the $\bar{d}/\bar{u}$ ratio at leading order at a large $Q^2$ set by the $W$ mass.
Presented in this talk are the latest preliminary results and analysis updates of $W^+$ and $W^-$ cross-section ratio measurements via lepton-decay tagging, using the STAR $pp$ collision data at a 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 cover the mid $(|\eta|<1)$ and intermediate rapidities $(1 < \eta < 2)$, probing the $\bar{d}/\bar{u}$ ratio within the proton momentum fraction range of $0.06 < x < 0.4$.
| Submitted on behalf of a Collaboration? | Yes |
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