T-odd effects in photon-jet production at the Tevatron

The angular distribution in photon-jet production in pp¯→γjetX is studied within a generalized factorization scheme taking into account the transverse momentum of the partons in the initial hadrons. Within this scheme an anomalously large cos2ϕcos2ϕ asymmetry observed in the Drell–Yan process could be attributed to the T-odd, spin and transverse momentum dependent parton distribution function h1⊥q(x,p⊥2). This same function is expected to produce a cos2ϕcos2ϕ asymmetry in the photon-jet production cross section. We give the expression for this particular azimuthal asymmetry, which is estimated to be smaller than the Drell–Yan asymmetry but still of considerable size for Tevatron kinematics. This offers a new possibility to study T-odd effects at the Tevatron.