McDonald, John
(1997)
*ucdcdc-based Affleck-Dine baryogenesis.*
Physical Review D, 55 (7).
pp. 4240-4251.
ISSN 0556-2821

## Abstract

We consider the possibility of a successful Affleck-Dine mechanism alone the u(c)d(c)d(c) direction in R-parity symmetric extensions of the minimal supersymmetric standard model (MSSM) which contain a gauge singlet superfield phi. Such gauge singlets commonly occur in extensions of the MSSM, for example, in models which seek to account for neutrino masses. We consider a two scalar Affleck-Dine mechanism, with the Rat direction stabilized by a nonrenormalizible superpotential term of the form (lambda/M)phi u(c)d(c)d(c) similar to(lambda/M)phi psi(3), where psi corresponds to the gauge nonsinglet flat direction, We give approximate solutions of the Scalar field equations of motion which describe the evolution of the condensates and show that the final baryon asymmetry in this case is suppressed relative to that expected from the conventional single scalar Affleck-Dine mechanism, based on a superpotential term of the form (lambda/4M)psi(4), by a factor [m(s)/(m(phi)+m(s))](1/2), where m(s), is the soft supersymmetry-breaking scalar mass and m(phi) is the supersymmetric phi mass. It is possible for the model to generate a baryon asymmetry even in the limit of unbroken B-L, so long as the gauge singlet condensate does not decay until after anomalous electroweak B+L violation is out of equilibrium following the electroweak phase transition. This condition is generally satisfied if all Dirac neutrino masses are less than around 10 keV. This class of Affleck-Dine models can, in principle, be experimentally ruled out, for example, by the observation of a Dirac mass for the mu or tau neutrino significantly larger than around 10 keV together with a mostly Higgsino LSP.