Signatures of Hypercharge Axions at Future Colliders

We devise a search for the hypercharge axion a hypothetical pseudoscalar that couples to the weak hypercharge topological density and could potentially explain the matter antimatter asymmetry in the observed universe If the axion exists it can be produced in colliders via vector boson fusion or in association with a photon or with a Z boson and detected by looking for its decay into photons or Z bosons The Standard Model background consists of processes producing photons and Z bosons with high transverse momenta and invariant mass equal to that of the axion We find that for certain values of the axion mass and mass scale both of the order of a TeV existing data from the Large Hadron Collider LHC can already put interesting constraints and in future colliders such as the High Luminosity LHC accessible detection range is increased significantly