Flavor Probes of MeV-GeV ALPs

by Andrea Thamm (University of Melbourne (AU))


Axion-like particles (ALPs) are well-motivated low-energy relics of high-energy extensions of the Standard Model which interact with the known particles through higher-dimensional operators suppressed by the mass scale of the new-physics sector. Starting from the most general dimension-5 interactions, I will discuss the evolution of the ALP couplings from the new-physics scale to energies below the scale of electroweak symmetry breaking and its effects on experimental probes of ALPs with MeV - GeV masses. In particular, I will present a comprehensive analysis of quark and lepton flavor observables and derive bounds on specific ALP models in which only a restricted set of ALP couplings to SM particles occurs at tree-level.