Photon Yield Optimization for the MARQ RICH Detector in the J-PARC E50 Experiment

The J-PARC E50 experiment will perform precision spectroscopy of charmed baryons (Y_c^*) via the π^- p → D^*- Y_c^* reaction to study diquark correlations in baryons, through which we expect to learn a fundamental aspect of non-perturbative QCD. This experiment requires excellent particle identification (PID) of kaons and pions from D^*- decays in the 2-16 GeV/c momentum range, which will be provided by a Ring Imaging Cherenkov (RICH) detector. The RICH detector uses a dual-radiator system of silica aerogel and gas in a mirror-focusing configuration. Maximizing photon efficiency is crucial for achieving the required PID performance. This work characterizes wavelength dependent photon losses from absorption in the silica aerogel radiator and its containment films. We also evaluate the optical performance of a light concentrator designed to increase the effective coverage of the Silicon Photomultiplier (SiPM) sensor array. These results are analyzed in conjunction with the Cherenkov production spectrum and the SiPM spectral response to build a comprehensive model of total photon yield. This study provides critical input for material selection and optical design choices to optimize the MARQ RICH detectors performance and physics reach.