Baryogenesis

The realisation that the electroweak anomaly can induce significant baryon number violation at high temperature and that the standard models of particle physics and cosmology contain all the ingredients needed for baryogenesis has led to vigourous search for viable models. The conclusions so far are that the Standard Model of particle physics cannot produce baryon asymmetry of required magnitude. It has too little $CP$ violation and sphaleronic transitions wipe out any asymme...

We review the current status of baryogenesis with emphasis on electroweak baryogenesis and leptogenesis. The first detailed studies were carried out for SU(5) GUT models where CP-violating decays of leptoquarks generate a baryon asymmetry. These GUT models were excluded by the discovery of B+L violating sphaleron processes at high temperatures. Yet a new possibility emerged, electroweak baryogenesis. Here sphaleron processes generate a baryon asymmetry during a strongly first...

We propose a new alternative for baryogenesis which resolves a number of the problems associated with GUT and electroweak scenarios, and which may allow baryogenesis even in modest extensions of the standard model. If the universe never reheats above the electroweak scale following inflation, GUT baryon production does not occur and at the same time thermal sphalerons, gravitinos and monopoles are not produced in abundance. Nevertheless, non-thermal production of sphaleron co...

I schematically, and very lightly, review some ideas that fuel model building in the field of baryogenesis. Due to limitations of space, and my expertise, this mini-review is incomplete and biased toward particle physics, especially supersymmetry.

The origin of the matter-antimatter asymmetry remains one of the most fundamental problems of cosmology. In this talk I present a novel scenario for baryogenesis at the electroweak scale, without the need for a first order phase transition. It is based on the out of equilibrium resonant production of long wavelength Higgs and gauge configurations, at the end of a period of inflation, which induces a large rate of sphaleron transitions, before thermalization at a temperature b...

The classical picture of GUT baryogenesis has been strongly modified by theoretical progress concerning two nonperturbative features of the standard model: the phase diagram of the electroweak theory, and baryon and lepton number changing sphaleron processes in the high-temperature symmetric phase of the standard model. We briefly review three viable models, electroweak baryogenesis, the Affleck-Dine mechanism and leptogenesis and discuss the prospects to falsify them. All mo...

Although the origin of matter-antimatter asymmetry remains unknown, continuing advances in theory and improved experimental limits have ruled out some scenarios for baryogenesis, for example the sphaleron baryogenesis at the electroweak phase transition in the standard model. At the same time, the success of cosmological inflation and the prospects for discovering supersymmetry at the LHC have put some other models in sharper focus. We review the current state of our understa...

I describe a new way for baryogenesis to proceed, which evades many of the problems of GUT and electroweak scenarios. If the reheat temperature after inflation is below the electroweak scale, neither GUT baryon production nor traditional electroweak baryogenesis can occur. However, non-thermal production of sphaleron configurations via preheating could generate the observed baryon asymmetry of the universe. Such low scale baryon production is particularly attractive since it ...

We study the cosmological evolution of asymmetries in the two-Higgs doublet extension of the Standard Model, prior to the electroweak phase transition. If Higgs flavour-exchanging interactions are sufficiently slow, then a relative asymmetry among the Higgs doublets corresponds to an effectively conserved quantum number. Since the magnitude of the Higgs couplings depends on the choice of basis in the Higgs doublet space, we attempt to formulate basis-independent out-of-equili...

The electroweak sphaleron process breaks the baryon number conservation within the realms of the Standard Model of particle physics (SM). Recently, it is pointed out that its decoupling may provide the out-of-equilibrium condition required for baryogenesis. In this paper, we study such a scenario taking into account the baryon-number wash-out effect of the sphaleron itself to improve the estimate. We clarify the amount of CP violation required for this scenario to explain the...