Measurements of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>W</mml:mi></mml:math> and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>Z</mml:mi><mml:mo stretchy="false">/</mml:mo><mml:msup><mml:mi>γ</mml:mi><mml:mo>*</mml:mo></mml:msup></mml:math> cross sections and their ratios in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>p</mml:mi><mml:mo>+</mml:mo><mml:mi>p</mml:mi></mml:math> collisions at RHIC
J. Adam, L. Adamczyk, J. R. Adams, J. K. Adkins, G. Agakishiev, M. M. Aggarwal, Z. Ahammed, I. Alekseev, D. M. Anderson, A. Aparin, E. C. Aschenauer, M. U. Ashraf, F. G. Atetalla, A. Attri, G. S. Averichev, V. Bairathi, K. N. Barish, A. Behera, R. Bellwied, A. Bhasin, J. Bielčík, J. Bielčíková, L. C. Bland, I. G. Bordyuzhin, J. D. Brandenburg, A. V. Brandin, J. M. Butterworth, H. Caines, M. Calderón de la Barca Sánchez, D. Cebra, I. Chakaberia, P. Chaloupka, B. K. Chan, F-H. Chang, Z. Chang, N. Chankova-Bunzarova, A. Chatterjee, D. Chen, Jian Chen, J. H. Chen, X. Chen, Z. Chen, J. Cheng, M. Cherney, M. Chevalier, S. Choudhury, W. Christie, X. Chu, H. J. Crawford, M. Csanád, M. Daugherity, T. G. Dedovich, I. M. Deppner, A. A. Derevschikov, L. Didenko, X. Dong, J. L. Drachenberg, J. C. Dunlop, T. Edmonds, N. Elsey, J. Engelage, G. Eppley, S. Esumi, O. Evdokimov, A. Ewigleben, O. Eyser, R. Fatemi, S. Fazio, P. Federic, J. Fedorišin, C. Feng, Y. Feng, P. Filip, E. Finch, Y. Fisyak, A. Francisco, Ł. Fulek, C. A. Gagliardi, T. Galatyuk, F. J. M. Geurts, S. M. Gibson, K. Gopal, X. Gou, D. Grosnick, W. Guryn, A. I. Hamad, A. Hamed, S. Harabasz, J. W. Harris, S. He, W. He, X. H. He, Y. He, S. Heppelmann, S. Heppelmann, N. Herrmann, Eric A. Hoffman, L. Holub, Y. Hong, S. Horvat
Abstract
We report on the $W$ and $Z/{\ensuremath{\gamma}}^{*}$ differential and total cross sections as well as the ${W}^{+}/{W}^{\ensuremath{-}}$ and $({W}^{+}+{W}^{\ensuremath{-}})/(Z/{\ensuremath{\gamma}}^{*})$ cross section ratios measured by the STAR experiment at RHIC in $p+p$ collisions at $\sqrt{s}=500\text{ }\text{ }\mathrm{GeV}$ and 510 GeV. The cross sections and their ratios are sensitive to quark and antiquark parton distribution functions. In particular, at leading order, the $W$ cross section ratio is sensitive to the $\overline{d}/\overline{u}$ ratio. These measurements were taken at high ${Q}^{2}\ensuremath{\sim}{M}_{W}^{2},{M}_{Z}^{2}$ and can serve as input into global analyses to provide constraints on the sea quark distributions. The results presented here combine three STAR datasets from 2011, 2012, and 2013, accumulating an integrated luminosity of $350\text{ }\text{ }{\mathrm{pb}}^{\ensuremath{-}1}$. We also assess the expected impact that our ${W}^{+}/{W}^{\ensuremath{-}}$ cross section ratios will have on various quark distributions, and find sensitivity to the $\overline{u}\ensuremath{-}\overline{d}$ and $\overline{d}/\overline{u}$ distributions.