ALPs and Heavy Hadron Chiral Perturbation Theory

Axion Like Particles (ALPs) belong to a well motivated class of particles which are part of a more complete UV theory. In this work, we initiate and present the inclusion of such ALPs or the conventional axions in the Heavy Hadron Chiral Perturbation Theory (HHChiPT) in a model independent effective lagrangian way. Such a framework is well suited for studying heavy to heavy quark flavour preserving transitions. For light ALPs, the limits on the ALP couplings (or their combinations) turn out to be independent of ALP mass. Radiative and leptonic decays of heavy vector mesons to corresponding heavy pseudoscalar mesons will be able to provide some of the most stringent constraints on ALPs, particularly the diagonal couplings.