J/\psi reconstruction efficiencies and resolutions with the Forward Calorimeter

Abstract

Monte Carlo simulations were done to estimate reconstruction efficiencies of J/psi mesons in the Forward Calorimeter that is proposed as an upgrade for the ALICE at CERN. The decay of a J/psi into an electron and a positron and the detector response was simulated. A J/psi was considered reconstructed if the reconstructed invariant mass calculated from two clusters was within 3 sigma of the J/psi mass. The sigma was obtained from a Gauss fit to the invariant mass. The energy dependent resolution was obtained as well as reconstruction efficiencies as a function of pT, energy and eta. Resolutions of approximately 70 MeV are obtained for a J/psi pT of 24 GeV/c. The resolution of the invariant mass distribution was found to be predominantly caused by the energy and position resolutions of the Forward Calorimeter. Reconstruction efficiencies over 80% were found for pT > 14 GeV/c, for E > 200 GeV and for 3.6 < eta < 4.