ALICE-PHOS: Acceptance and efficiency correction factors $p- p \to \pi^0 + X$ at 10-TeV

In ultra-relativistic Heavy-Ion Collisions (HIC), the properties of the quark gluon plasma (QGP) can be explored, in particular, via measurements of neutral pions. The $\pi^0$ is an important probe for both proton and heavy ion physics. In the former case, $\pi^0$ production provides an important mean of testing pQCD as well as useful data to constrain current and future theoretical models. In the latter case, $\pi^0$ measurements will serve as a baseline for exploring the nature of the HIC hard scattering. In the ALICE experiment, $\pi^0$ mesons are identified as they decay into two photons ($\pi^0 \to \gamma \gamma$) using the high-resolution photon spectrometer (PHOS). PHOS will measure $\pi^0$ transverse momentum over a wide range, from hundreds of MeV/c to several tens of GeV/c. An estimation of $\pi^0$ production cross-section in proton–proton collisions is calculated in a next-to-leading order (NLO) approximation and first presented. The $\pi^0$ geometrical acceptance and the identification efficiency along with the analysis on the invariant mass are the two important correction factors for obtaining a realistic $\pi^0$ spectrum discussed in this paper.