Analysis of NA62 events with RICH signals off the Cherenkov ring

The Ring-Imaging Cherenkov (RICH) detector of the NA62 experiment is a key component for charged-particle identification, providing precise measurements of particle velocity through the detection of Cherenkov radiation. The performance of the RICH relies on the accurate reconstruction of Cherenkov rings formed by photons reflected by a segmented mirror system and detected on a photon-sensitive plane. This thesis presents a detailed study of non-ideal RICH hit patterns, commonly referred to as spurious hits, which deviate from the expected ring topology and may affect the quality of Cherenkov ring reconstruction. Using reconstructed NA62 data from two different running periods, a robust hit- and event-level classification framework is developed to distinguish how the events without spurious hits and events with atleast one spurious hits behave based on spatial observables. The analysis investigates the dependence of spurious-hit behaviour on event topology, hit multiplicity, and track position on the RICH mirror plane, allowing the identification of region-dependent effects. Comparative studies between run periods are performed to assess the stability of the observed features. The results provide a quantitative characterization of events with atleast one spurious-hit, two spurious-hit and events with more than two spurious-hit in the NA62 RICH detector.