Search for New Physics in ρ0 Meson Decays in the NA64 Experiment

The NA64 experimental setup is a universal detector designed to test a wide range of models beyond the Standard Model. Some of these models predict the existence of light dark matter particles, whose presence can be inferred from indirect evidence. The NA64 experiment is searching for such particles, specifically the dark photon A 1pt ' —a vector mediator between ordinary and dark matter. This paper focuses on simulating a specific dark photon production channel: the decay of a ρ ⁰ meson into a dark photon, which subsequently decays into dark matter particles.