Signatures of hypercharge axions in colliders - art. no. 015001

If, in addition to the standard model fields, a new pseudoscalar field that couples to hypercharge topological number density, the hypercharge axion, exists, it can be produced in colliders in association with photons or Z bo sons and detected by looking for its decay into photons or Z's. For a range of masses below 1 TeV and coupling above a fraction of 1/TeV, existing dat a from CERN LEP II and the Fermilab Tevatron can already achieve interestin g constraints, and in future colliders the accessible detection range will be increased significantly. The hypercharge axion can help in explaining th e matter-antimatter asymmetry in the universe.