Baryogenesis from leptogenesis in SO(10) models

We discuss the baryogenesis via leptogenesis mechanism within the supersymmetric and nonsupersymmetric SO(10) models. We find that the nonsupersymmetric model, endowed with an intermediate scale, is generally favoured, unless some fine tuning occurs in the supersymmetric case.     

Bino-driven electroweak baryogenesis with highly suppressed electric dipole moments

It is conventional wisdom that successful electroweak baryogenesis in the Minimal Supersymmetric extension of the Standard Model (MSSM) is in tension with the non-observation of electric dipole moments (EDMs), since the level of CP-violation responsible for electroweak baryogenesis is believed to generate unavoidably large EDMs. We show that CP-violation in the bino–Higgsino sector of the MSSM can account for successful electroweak baryogenesis without inducing large EDMs. This observation weakens the correlation between electroweak baryogenesis and EDMs, and makes the bino-driven electroweak baryogenesis scenario the least constrained by EDM limits. Taking this observation together with the requirement of a strongly first-order electroweak phase transition, we argue that a bino-driven scenario with a light stop is the most phenomenologically viable MSSM electroweak baryogenesis scenario.     

Helical magnetic fields from sphaleron decay and baryogenesis

Many models of baryogenesis rely on anomalous particle physics processes to give baryon number violation. By numerically evolving the electroweak equations on a lattice, we show that baryogenesis in these models creates helical cosmic magnetic fields, though the helicity created is smaller than earlier analytical estimates. After a transitory period, electroweak dynamics is found to conserve the Chern-Simons number and the total electromagnetic helicity. We argue that baryogenesis could lead to magnetic fields of nano-Gauss strength today on astrophysical length scales. In addition to being astrophysically relevant, such helical magnetic fields can provide an independent probe of baryogenesis and CP violation in particle physics.     

Baryogenesis in a flat direction with neither baryon nor lepton charge

We present a new mechanism of spontaneous baryogenesis. Usually such mechanisms require a derivative coupling between a scalar field and baryon current. In our model, the scalar field instead derivatively couples to a current associated with some global symmetry U(1)(Q). In this case, baryogenesis is still possible provided that an interaction exists, which violates the baryon and U(1)(Q) symmetries simultaneously. As a concrete example, we discuss baryogenesis in a flat direction with neither baryon nor lepton charge.     

Baryogenesis via leptogenesis in multi-field inflation

In multi-field reheating after modular j-inflation we investigate the conditions under which baryogenesis via non-thermal leptogenesis can be successfully realized. We introduce three heavy right-handed neutrinos to the non-supersymmetric Standard Model of particle physics, assuming hierarchical neutrino masses. Considering a typical mass for the first right-handed neutrino of the order of \(10^{11}\) GeV, suggested from the seesaw mechanism and also from concrete SO(10) grand unification models, we obtain the allowed parameter space for viable baryogenesis. An upper bound for the inflaton mass as well as a lower bound for its branching ratio to the pair of lightest right-handed neutrinos are found and reported.     

Electroweak baryogenesis

After a short general introduction to baryogenesis — the creation of a baryon asymmetry in our universe (BAU) — I will highlight some old and more recent models of electroweak baryogenesis: modifications of the Standard Model (SM), in particular supersymmetric ones as the MSSM, NMSSM, nMSSM, BMSSM, νμMSSM. I will also stress the role of electric dipole moments (EDMs) in limiting the CP violation needed for baryogenesis.     

Single field baryogenesis

We propose a new variant of the Affleck-Dine baryogenesis mechanism in which a rolling scalar field couples directly to left- and right-handed neutrinos, generating a Dirac mass term through neutrino Yukawa interactions. In this setup, there are no explicitly CP violating couplings in the Lagrangian. The rolling scalar field is also taken to be uncharged under the B - L quantum numbers. During the phase of rolling, scalar field decays generate a nonvanishing number density of left-handed neutrinos, which then induce a net baryon number density via electroweak sphaleron transitions.     

Baryogenesis in Fresh Inflation

I study the possibility of baryogenesis can take place in fresh inflation. I find that it is possible that violation of baryon number conservation can occur during the period out-of-equilibrium in this scenario. Indeed, baryogenesis could be possible in the range of times (10⁹ – 10¹²) G^1/2, before the thermal equilibrium is restored at the end of fresh inflation.     

Baryogenesis

Developments in understanding of baryogenesis are reviewed. We start with early motivations and the proposals in the context of GUTs. Next, the importance of the sphaleron solution and its implications are discussed. Studies of the Standard Model reveal that the latter has a Higgs structure incompatible with existence of observed B asymmetry. We then discuss a generic scenario for electroweak baryogenesis relying on bubble wall dynamics. We also summarise the status of the MSSM, and alternative scenarios utilising topological defects as the source of non-equilibrium behaviour and leptogenesis     

Baryon asymmetry of the universe from evaporation of primordial black holes

The process of baryogenesis through evaporation of black holes formed at the end of the inflation phase is considered. The increase in black hole mass due to accretion from the surrounding radiation after reheating is taken into account. It is shown that the influence of the accretion on the baryogenesis is important only in the case where the initial values of black hole mass are larger than ～10⁴ g. The behavior of the calculated baryon asymmetry as a function of model parameters is studied.     

Coherent baryogenesis

We propose a new baryogenesis scenario based on coherent production and mixing of different fermionic species. The mechanism is operative during phase transitions, at which the fermions acquire masses via Yukawa couplings to scalar fields. Baryon production is efficient when the mass matrix is nonadiabatically varying, nonsymmetric and when it violates CP and B-L directly, or some other charges that are eventually converted to B-L. We first consider a toy model, which involves two mixing fermionic species, and then a hybrid inflationary scenario embedded in a supersymmetric Pati-Salam GUT. We show that, quite generically, baryon excess in accordance with observation can result.     

Probing the seesaw mechanism with neutrino data and leptogenesis

We use the current low-energy neutrino data to understand the structure of the neutrino mass matrix. Considering this information and assuming hierarchical neutrino Yukawa couplings, we use the seesaw formula to study the properties of the heavy right-handed neutrinos N_i. We find that successful baryogenesis via leptogenesis requires mass degeneracy and maximal mixing of N₁ and N₂.     

Baryogenesis and Electric Dipole Moments in Minimal Supersymmetric Standard Model

We briefly review the issues related to electroweak baryogenesis in minimal supersymmetric standard model (MSSM). The constraints from electric dipole moments of electron and neutron are emphasized.     

Electroweak phase transition in the minimal supersymmetric standard model: 4-dimensional lattice simulations

Lattice results show no standard model (SM) electroweak phase transition (EWPT) for Higgs masses approximately 72 GeV, which is below the present experimental limit. Perturbation theory and 3-dimensional simulations indicate an EWPT in the minimal supersymmetric SM (MSSM) that is strong enough for baryogenesis up to m(h) approximately 105 GeV. In this Letter we present the results of our large scale 4-dimensional MSSM EWPT simulations. We carried out infinite volume and continuum limits and found a transition whose strength agrees well with perturbation theory, allowing MSSM electroweak baryogenesis at least up to m(h) = 103+/-4 GeV. We determined the properties of the bubble wall.     

Status of electroweak phase transition and baryogenesis

I review recent progress on the electroweak phase transition and baryogenesis, focusing on the minimal supersymmetric Standard Model as the source of new physics.     

Baryogenesis in f(R,T) Gravity

We study gravitational baryogenesis in the context of f(R, T) gravity where the gravitational Lagrangian is given by a generic function of the Ricci scalar R and the trace of the stress-energy tensor T. We explore how this type of modified gravity is capable to shed light on the issue of baryon asymmetry in a successful manner. We consider various forms of baryogenesis interaction and discuss the effect of these interaction terms on the baryon to entropy ratio in this setup. We show that baryon asymmetry during the radiation era of the expanding universe can be non-zero in this framework. Then, we calculate the baryon to entropy ratio for some specific f(R, T) models and by using the observational data, we give some constraints on the parameter spaces of these models.     

Gravitational baryogenesis models comparison in f(R) gravity

We have studied the gravitational baryogenesis in $f\left(R\right)$ theory of gravity with an anisotropic Bianchi I space-time. The matter field is considered to be that of perfect fluid. Two models pertaining to specific form of Ricci scalar have been presented. The baryon-to-entropy ratio has been derived with some specific form of Ricci scalar in an an anisotropic background. The gravitational baryogenesis is examined and its behaviors are studied.     

Baryogenesis in f(R,T) Gravity

We study gravitational baryogenesis in the context of f(R, T) gravity where the gravitational Lagrangian is given by a generic function of the Ricci scalar R and the trace of the stress-energy tensor T. We explore how this type of modified gravity is capable to shed light on the issue of baryon asymmetry in a successful manner. We consider various forms of baryogenesis interaction and discuss the effect of these interaction terms on the baryon to entropy ratio in this setup. We show that baryon asymmetry during the radiation era of the expanding universe can be non-zero in this framework. Then, we calculate the baryon to entropy ratio for some specific f(R, T) models and by using the observational data, we give some constraints on the parameter spaces of these models.     

Gravitational Baryogenesis Revised

Gravitational baryogenesis is reviewed. Is is shown that the non-minimal coupling of the curvature scalar to baryonic current leads to a modification of the gravitational equations, which become higher order. It is found that these equations have unstablesolution distorted the Standard Cosmological Model.     

Particle decay and bulk dissipative stress in the early universe

In this paper we show that the combined action of particle decay and a physically motivated dissipative bulk stress can lead to a period of generalized inflation and temperature increase. This effect may have occurred at the baryogenesis era.