Electromagnetic Calorimeter Calibration with $\pi^{0}$

Abstract

Several methods can be used in order to achieve precise calibration of the LHCb Electromagnetic Calorimeter (ECAL) once reasonable cell equalization has been reached. At low transverse energy, the standard calibration procedure is an iterative method based on the fit of the $\gamma\gamma$ invariant mass distribution for each cell of the decay $\pi^{0}\to\gamma\gamma$ with resolved photons. A new technique for generating the combinatorial background of such decays directly from data has been developed. Knowledge of the background could allow an alternative calibration method based on a event by event fit of the same $\gamma\gamma$ invariant mass distribution where contributions from groups of cells are considered in a single fit. The background generation procedure and this possible new calibration method are presented in this poster, in addition to an overview of the LHCb Calorimetry system and ECAL calibration techniques