Related papers: Leptogenesis via $LH_{u}$ flat direction with a ga…
We reanalyze the supersymmetric leptogenesis model by one of the authors (HM) and Yanagida based on \tilde{L} = H_u flat direction in detail. We point out that the appropriate amount of baryon asymmetry can be generated in this model with…
We study Affleck-Dine leptogenesis via the L H_u flat direction in supersymmetric theories. We find that the baryon asymmetry is enhanced when the energy scale of the inflation is sufficiently low. Especially, we consider models of low…
Leptogenesis constitues a very simple scenario to achieve the baryon asymmetry that we observe today. It requires only the presence of right handed neutrinos (which arise very naturally in many extensions of the Standard Model) and depends…
Supersymmetric thermal leptogenesis with a hierarchical right-handed neutrino mass spectrum requires the mass of the lightest right-handed neutrino to be heavier than about 10^9 GeV. This is in conflict with the upper bound on the reheating…
We investigate the leptogenesis via decays of heavy Majorana neutrinos which are produced non-thermally in inflaton decays. We make a comprehensive study on the leptogenesis assuming various supersymmetric (SUSY) models for hybrid, new and…
Leptogenesis in supersymmetric model is discussed comprehensively and in detail. In the first half, we discuss several leptogenesis mechanisms by the decay of heavy right-handed neutrino, which include the standard thermal leptogenesis,…
Motivated by our earlier paper \cite{am}, we discuss how the infamous gravitino problem has a natural built in solution within supersymmetry. Supersymmetry allows a large number of flat directions made up of {\it gauge invariant}…
The minimal gauged U(1)$_{L_\mu-L_\tau}$ model is a simple extension of the Standard Model and has a strong predictive power for the neutrino sector. In particular, the mass spectrum and couplings of heavy right-handed neutrinos are…
The nonsupersymmetric as well as the supersymmetric hybrid inflationary model is reviewed. The scenario of baryogenesis via a primordial leptogenesis is discussed and the role of the nonperturbative electroweak sphaleron effects is…
We perform a detailed analysis on Affleck-Dine leptogenesis taking into account the thermal effects on the dynamics of the flat direction field $\phi$. We find that an extremely small mass for the lightest neutrino $\nu_1$, ${m_\nu}_1\lsim…
We discuss resonant leptogenesis arising from the decays of two nearly-degenerate right-handed neutrinos, identified as the inflaton and stabiliser superfields in a model of chaotic sneutrino inflation. We compare an analytical estimate of…
We discuss leptogenesis in a realistic supersymmetric model of inflation with a low reheat temperature 1-10 GeV. The lepton asymmetry is generated by a decaying right handed sneutrino, which is produced after inflation during preheating.…
We explore an anomaly-free ${\textrm U}(1)$ gauge extended beyond the Standard model (BSM) framework, to account for the baryon asymmetry of the Universe, along with arranging for tiny neutrino mass. Neutrino masses are generated via…
We discuss the non-thermal leptogenesis in the scheme of 5D orbifold SO(10) GUT with the smooth hybrid inflation. With an unambiguously determined Dirac Yukawa couplings and an assumption for the neutrino mixing matrix of the tri-bimaximal…
The gravitino problem gives a severe constraint on the thermal leptogenesis scenario. This problem leads us to consider some alternatives to it if we try to keep the gravitino mass around the weak scale $m_{3/2} \sim 100$ GeV. We consider,…
We show that in supersymmetric models with gauged B-L symmetry, there is a new source for cosmological lepton asymmetry. The Higgs bosons responsible for B-L gauge symmetry breaking decay dominantly into right-handed sneutrinos \tilde{N}…
If the $B-L$ symmetry is gauged with the addition of right-handed neutrinos, the standard model $B-L$ current is anomalous with respect to the $B-L$ gauge field itself. Then, the anomaly relation implies that the magnetic helicity of the…
We study the thermal leptogenesis in the $E_6\times U(1)_A$ SUSY GUT model in which realistic masses and mixings of quarks and leptons can be realized. We show that the sufficient baryon number can be produced by the leptogenesis in the…
If the baryon asymmetry in the present universe is generated by decays of the $L H_u$ flat direction, the observed baryon asymmetry requires the mass of the lightest neutrino to be much smaller than the mass scale indicated from the…
A typical problem of the leptogenesis scenario is the mismatch between the maximum reheat temperature implied by gravitino overproduction bound and the minimum temperature required to create thermally the lightest right-handed neutrino. We…