Improving η-Meson Reconstruction in the ALICE Experiment

A statistical method for extracting the η → γγ signal upon rejecting those γ clusters that form pairs with invariant masses close to that of the π$^{0}$ meson is proposed. The η selection efficiency (the ratio between the numbers of selected and produced η mesons) and the signal-to-background ratio as a function of the η transverse momentum are obtained using a template of proton–proton collisions at $\sqrt s $ = 13 TeV simulated with PYTHIA 8.2 (with Monash-2013 tuning). The proposed method provides for an η → γγ selection efficiency of ~80% and for a 20–50% increase in the signal-to-background ratio compared to currently implemented techniques.