Simulation-based Sensitivity Study of short-lived Axion-like Particles in B Meson Decays at the Belle II Experiment

Axion-Like-Particles (ALPs) are a well motivated extension to the Standard Model. They are light, pseudoscalar particles which are dominantly interacting with Standard Model gauge bosons. As a result ALPs can be produced in a flavor-changing neutral current transition by its coupling to W bosons. Subsequently, the ALP dominantly decays into two photons, which makes the decay of a charged B meson to a charged K meson and an axion, which subsequently decays to two photons, a promising process for measuring the coupling to W bosons. Such decays can be studied at e+ e− colliders like the Belle II experiment. In this thesis a simulation-based sensitivity study of this process is performed by reconstructing the B meson and examining the invariant di-photon mass distribution. The study is performed with ALPs in mass range 0.1-4.6 GeV and zero lifetime. The expected limits are comparable to the results of the BaBar Collaboration, who conducted a similar search.