We calculate the baryon asymmetry of the Universe in the Z3-invariant
Next-to-Minimal Supersymmetric Standard Model where the interactions of the
singlino provide the necessary source of charge and parity violation. Using the
closed time path formalism, we derive and solve transport equations for the
cases where the singlet acquires a vacuum expectation value (VEV) before and
during the electroweak phase transition. We perform a detailed scan to show how
the baryon asymmetry varies throughout the relevant parameter space. Our
results show that the case where the singlet acquires a VEV during the
electroweak phase transition typically generates a larger baryon asymmetry,
although we expect that the case where the singlet acquires a VEV first is far
more common for any model in which parameters unify at a high scale. Finally,
we examine the dependence of the baryon asymmetry on the three-body
interactions involving gauge singlets.Comment: 24 pages, version submitted to the journa
