First principle derivation of semiclassical force for electroweak baryogenesis

We perform a systematic gradient expansion on kinetic equations and derive the CPviolating semiclassical force for fermions propagating in presence of a CP-violating wall at a first order electroweak phase transition. The force appears at order h̄ in the flow term of the kinetic equation and agrees with the semiclassical force used for baryogenesis computations. In particular we consider the force for charginos in both the MSSM and NMSSM. We then study the continuity equations for the vector and axial vector currents and stress the role of the latter as the one containing baryogenesis sources. We also show that there is no CP-violating force for bosons to order h̄ in gradient expansion. •[email protected] T.Prokopec@, M.G.Schmidt@, [email protected]