Searching for Axionlike Particles in Flavor-Changing Neutral Current Processes

We propose new searches for axionlike particles (ALPs) produced in flavor-changing neutral current (FCNC) processes. This proposal exploits the often-overlooked coupling of ALPs to W +/- bosons, leading to FCNC production of ALPs even in the absence of a direct coupling to fermions. Our proposed searches for resonant ALP production in decays such as B -> K-(*()) a, a -> gamma gamma and K -> pi a, a ->gamma gamma could greatly improve upon the current sensitivity to ALP couplings to standard model particles. We also determine analogous constraints and discovery prospects for invisibly decaying ALPs.