Figure 1

Fit of the dielectron cross section as a function of mass in INEL (left) and HM (right) pp collisions in the $2 < p_{\rm T,ee} < 3$ GeV/$c$ interval with a three-component fit function to extract the fraction of direct photons to inclusive photons $r$. Statistical and systematic uncertainties of the data are displayed as vertical bars and boxes, respectively. The integrated luminosities of $\mathcal{L}^{\rm MB}_{\rm int} = 29.8 \pm 0.6$ nb$^{-1}$ and $\mathcal{L}^{\rm HM}_{\rm int} = 5.8 \pm 0.1$ pb$^{-1}$ (2% global uncertainty not shown in the Figure) are used to calculate the dielectron cross sections $\rm{d}\sigma/\rm{d}m_{\rm{ee}}$ from the differential dielectron yield per event. The resulting fraction of direct photons $r$ is shown together with its statistical uncertainty. The templates for dielectrons from LF, HF and direct photons are shown as different dashed lines, and the resulting fit is shown as a solid magenta line. The contributions from $\pi^{0}$ and $\eta$ mesons are also shown as separate lines. See the Appendix A of this letter for the fits of the dielectron cross section in other pair transverse momentum intervals (Figs.A.1 & A.2).