I examine the effect of the thermal background on the mechanism of electroweak baryogenesis. Firstly, I model the effect of collisions by solving the Schrodinger equation in the presence of a potential representing the bubble of phase transition of the Higgs field and a series of delta functions simulating the collisions amongst the particles. This "delta-functions recurrency technique" is then applied to the case of relativistic particles by solving the Dirac equation in the presence of similar potentials.

Secondly, I attempt to model the interaction by a totally distinct formalism that incorporates the effect of the exchange of momentum during a collision between the particles of the thermal background. To this end, I examine the evolution of the density matrix of a system subjected to an interaction, modeling the effect of the thermal background on baryogenesis. This formalism is applied in both the nonrelativistic and relativistic cases.

It will be shown that the generated baryon asymetry can be reduced by a factor of as much as 100 by the effects of the collisions.

Thursday, April 20th 2000, 13:00
Ernest Rutherford Physics Building, room 326