Inclusive J/ψ cross section in proton-proton collisions at the center-of-mass energy 13TeV with ALICE

Abstract

This thesis describes the inclusive cross section measurement of the J/ψ meson in the di-electron channel measured at mid-rapidity in proton-proton collisions at the center-of-mass energy 13 TeV. The analyzed data sample includes all proton-proton data recorded by the ALICE detector during the period 2016 to 2017 and consists of 1.4 billion minimum bias events. The electron track selection relies on particle identification from the Time Projection Chamber in the ALICE central barrel. The raw J/ψ signal is extracted through bin counting in the signal window 2.92 ≤ m_inv., e+e− ≤ 3.16 GeV/c^2 of the invariant mass spectrum after background subtraction. The background is estimated combining an invariant mass spectrum built from pairs from different events with an empirical fit. The obtained yield is corrected for the detector acceptance and efficiency determined from a Monte Carlo sample anchored to the corresponding data sample. The inclusive cross section is dσ/dy = 9.46 ± 0.28 (stat.) ± 0.43 (syst.) ± 0.48 (global) µb.