Postsphaleron baryogenesis

We present a new mechanism for generating the baryon asymmetry of the Universe directly in the decay of a singlet scalar field S-r with a weak scale mass and a high dimensional baryon number-violating coupling. Unlike most currently popular models, this mechanism, which becomes effective after the electroweak phase transition, does not rely on the sphalerons for inducing a nonzero baryon number. CP asymmetry in S-r decay arises through loop diagrams involving the exchange of W-+/- gauge bosons and is suppressed by light quark masses, leading naturally to a value of eta(B)similar to 10(-10). The simplest realization of this idea which uses a six quark Delta B=2 operator predicts colored scalars accessible to the CERN Large Hadron Collider and neutron-antineutron oscillation within reach of the next-generation experiments.