Baryogenesis

We consider origins of the baryon asymmetry which we observe today. We review the progress of electroweak-scale baryogenesis, and show a new mechanism, string-scale baryogenesis.

This talk is based on work performed with Graham Ross and is a very concise summary of our soon to be published paper. Here we present a revision of the analysis of sphaleron baryon-number violating processes in the standard model including lepton-mass effects. We find the surprising result that a GUT-scale matter-asymmetry can survive the $B$ and $L$ violating sphaleron interactions even though ($B- L$) is conserved and equals zero for all temperatures. We extend the analysi...

These lectures provide a pedagogical review of the present status of theories explaining the observed baryon asymmetry of the Universe. Particular emphasis is given on GUT baryogenesis and electroweak baryogenesis. The key issues, the unresolved problems and the very recent developments, such as GUT baryogenesis during preheating, are explained. Some exercises (and their solution) are also provided.

A review of the present state of the baryogenesis is given with an emphasis on electroweak baryogenesis. Technical details of the numerous models cosidered in the literature are not elaborated but unresolved problems of the issue are considered. Different logically possible alternatives of the electroweak scenarios are presented. A possible impact of bariogenesis on the universe structure formation is discussed.

A brief review of the fundamental ideas behind electroweak baryogenesis is presented. Since a successful implementation of these ideas requires an extension of the minimal standard model, I comment on the necessary physics and how experimental constraints make these scenarios testable at the LHC, and perhaps at existing colliders.

We provide an up to date account of progress in understanding the origin of the observed baryon asymmetry of the universe. While our primary goal is to be current, we have attempted to give a pedagogical introduction to the primary areas of research in this field, giving a detailed description of the different scenarios. The very recent developments in GUT baryogenesis, leptogenesis, electroweak baryogenesis and the Affleck-Dine mechanism are presented. In particular, we focu...

Baryogenesis during the electroweak phase transition is a plausible scenario for for the origin of matter in the Universe. Furthermore, it has the advantage over other scenarios in that one can imagine that much of the physics involved may be experimentally probed before long. In the past year a consensus has developed about major mechanisms involved. In this talk I give an overview of the standard picture, and discuss briefly the advances over the past year that suggest elec...

We reconsider the GUT-baryogenesis mechanism for generating the baryon asymmetry of the Universe. The baryon asymmetry is produced by the out of equilibrium decay of coloured Higgs bosons at the GUT scale, conserving B-L. If neutrinos are Majorana particles, lepton number violating interactions erase the lepton number excess, but part of the baryon asymmetry may be preserved, provided those interactions are not in thermal equilibrium when the sphaleron processes become effect...

In the following work we consider the possibility of explaining the observed baryon number asymmetry in the universe from simple baryon number violating modifications, involving massive scalar bosons, to the Standard Model. In these cases baryon number violation is mediated through a combination of Yukawa and scalar self-coupling interactions. Starting with a previously compiled catalogue of baryon-number violating extensions of the Standard Model, we identify the minimal sub...

If the present baryon-asymmetry is due to a Planck or GUT-scale matter asymmetry then baryon- or lepton-number violating processes are constrained by the condition that they do not subsequently erase this asymmetry. We present a revision of the analysis of sphaleron baryon-number violating processes in the standard model including lepton-mass effects. We find the surprising result that a GUT-scale matter-asymmetry can survive the $B$ and $L$ violating sphaleron interactions e...