Cross Section and Parity-Violating Spin Asymmetries of W± Boson Production in Polarized p+p Collisions at s=500 GeV

Le résumé fourni par la source

Large parity-violating longitudinal single-spin asymmetries ${A}_{L}^{{e}^{+}}=\ensuremath{-}{0.86}_{\ensuremath{-}0.14}^{+0.30}$ and ${A}_{L}^{{e}^{\ensuremath{-}}}={0.88}_{\ensuremath{-}0.71}^{+0.12}$ are observed for inclusive high transverse momentum electrons and positrons in polarized $p+p$ collisions at a center-of-mass energy of $\sqrt{s}=500\text{ }\text{ }\mathrm{GeV}$ with the PHENIX detector at RHIC. These ${e}^{\ifmmode\pm\else\textpm\fi{}}$ come mainly from the decay of ${W}^{\ifmmode\pm\else\textpm\fi{}}$ and ${Z}^{0}$ bosons, and their asymmetries directly demonstrate parity violation in the couplings of the ${W}^{\ifmmode\pm\else\textpm\fi{}}$ to the light quarks. The observed electron and positron yields were used to estimate ${W}^{\ifmmode\pm\else\textpm\fi{}}$ boson production cross sections for the ${e}^{\ifmmode\pm\else\textpm\fi{}}$ channels of $\ensuremath{\sigma}(pp\ensuremath{\rightarrow}{W}^{+}X)\ifmmode\times\else\texttimes\fi{}\mathrm{BR}({W}^{+}\ensuremath{\rightarrow}{e}^{+}{\ensuremath{\nu}}_{e})=144.1\ifmmode\pm\else\textpm\fi{}21.2(\mathrm{stat}{)}_{\ensuremath{-}10.3}^{+3.4}(\mathrm{syst})\ifmmode\pm\else\textpm\fi{}21.6(\mathrm{norm})\text{ }\text{ }\mathrm{pb}$, and $\ensuremath{\sigma}(pp\ensuremath{\rightarrow}{W}^{\ensuremath{-}}X)\ifmmode\times\else\texttimes\fi{}\mathrm{BR}({W}^{\ensuremath{-}}\ensuremath{\rightarrow}{e}^{\ensuremath{-}}{\overline{\ensuremath{\nu}}}_{e})=31.7\ifmmode\pm\else\textpm\fi{}12.1(\mathrm{stat}{)}_{\ensuremath{-}8.2}^{+10.1}(\mathrm{syst})\ifmmode\pm\else\textpm\fi{}4.8(\mathrm{norm})\text{ }\text{ }\mathrm{pb}$.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.