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Particles and Fields

Eur. Phys. J. C 20, 695-711 (2001)
DOI: 10.1007/s100520100655

Bubble walls, CP-violation and electroweak baryogenesis in the MSSM

S.J. Huber1, P. John2 and M.G. Schmidt3

1  Bartol Research Institute, 217 Sharp Lab, Newark, DE 19716, USA
2  Instituto de Estructura de la Materia (CSIC), Serrano 123, 28006 Madrid, Spain
3  Institut für Theoretische Physik, Philosophenweg 16, 69120 Heidelberg, Germany


(Received: 5 February 2001 / Published online: 8 June 2001 -© Springer-Verlag / Società Italiana di Fisica 2001 )

We discuss the generation of the baryon asymmetry by a strong first order electroweak phase transition in the early universe, particularly in the context of the MSSM. This requires a thorough numerical treatment of the bubble wall profile in the case of two Higgs fields. CP-violating complex particle masses varying with the Higgs field in the wall are essential. Since in the MSSM there is no indication of spontaneous CP-violation around the critical temperature (contrary to the NMSSM) we have to rely on standard explicit CP-violation. Using the WKB appro xi mation for particles in the plasma we are led to Boltzmann transport equations for the difference of left-handed particles and their CP-conjugates. This asymmetry is finally transformed into a baryon asymmetry by out of equilibrium sphaleron transitions in the symmetric phase. We solve the transport equations and find a baryon asymmetry depending mostly on the CP-violating phases and the wall velocity.

© Società Italiana di Fisica, Springer-Verlag 2001