"Figure 7" of "Measurement of the $W \to e \nu$ and $Z/\gamma^* \to e^+e^-$ Production Cross Sections at Mid-rapidity in Proton-Proton Collisions at $\sqrt{s}$ = 500 GeV"

We report measurements of the charge-separated $W^{+(−)} \to e^{+(−)} + \nu_{e}(\overline{\nu}_{e})$ and $Z/\gamma^{*} \to e^{+}e^{−}$ production cross sections at mid-rapidity in proton-proton collisions at $\sqrt{s}$ = 500 GeV. These results are based on 13.2 $pb^{−1}$ of data recorded in 2009 by the STAR detector at RHIC. Production cross sections for W bosons that decay via the $e\nu$ channel were measured to be $\sigma(pp \to W^{+}X)·BR(W^{+} \to e^{+} \nu_{e})$ = 117.3 $\pm$ 5.9(stat) $\pm$ 6.2(syst) $\pm$ 15.2(lumi) pb, and $\sigma(pp \to W^{−}X)·BR(W^{−} \to e^{−}\overline{\nu}_{e})$ = 43.3 $\pm$ 4.6(stat) $\pm$ 3.4(syst) $\pm$ 5.6(lumi) pb. For $Z/\gamma^{*}$ production, $\sigma(pp \to Z/\gamma^{∗} X) · BR(Z/\gamma^{*} \to e^{+}e^{−})$ = 7.7 $\pm$ 2.1(stat) ${}^{+0.5}_{-0.9}$(syst) $\pm$ 1.0(lumi) pb for di-lepton invariant masses $m_{e^{+}e^{-}}$ between 70 and 110 GeV/$c^{2}$. First measurements of the W cross section ratio, $\sigma(pp \to W^{+}X)/\sigma(pp \to W^{-}X)$, at $\sqrt{s}$ = 500 GeV are also reported. Theoretical predictions, calculated using recent parton distribution functions, are found to agree with the measured cross sections.