Leptogenesis Scenarios via Non-Thermally Produced Right-handed Neutrino and Sneutrino in Supersymmetric Seesaw Model

We reconsidered leptogenesis scenario from right-handed (s)neutrino produced by the decay of inflaton. Besides the well-investigated case that the neutrino decays instantaneously after the production, leptogenesis is possible if neutrino decays after it dominates the universe. In the latter case, right-handed (s)neutrino can decay either while it is relativistic or after it becomes non-relativistic. Especially, the first case has not been discussed seriously in literatures. Resultant lepton asymmetry and constraints from the gravitino problem are studied in broad parameter region, including all cases of this scenario. It is also shown how this leptogenesis scenario depends on the parameters, the inflaton decay rate (the reheating temperature), the right-handed neutrino mass, the washout parameter, and the constraint from the gravitino problem. Leptogenesis from relativistic neutrino decay is interesting because both thermal and non-thermal gravitino problems can be relaxed.Comment: 17 pages, 6 figure

Light Higgs boson scenario in the SUSY seesaw model

It is demonstrated that the light Higgs boson scenario, which the lightest Higgs mass is less than the LEP bound, mh > 114.4 GeV, is consistent with the SUSY seesaw model. With the assumptions of the universal right-handed neutrino mass and the hierarchical mass spectrum of the ordinary neutrinos, the bounds for the right-handed neutrino mass is investigated in terms of lepton flavor violating charged lepton decays. We also discuss the effect of the modification of renormalization group equations by the right-handed neutrinos on the b to s gamma process and the relic abundance of dark matter in the light Higgs boson scenario.Comment: 17 pages, 5 figure

Leptogenesis via multiscalar coherent evolution with supersymmetric neutrino see-saw

A novel scenario of leptogenesis is investigated in the supersymmetric neutrino see-saw model. The right-handed sneutrino ${\tilde N}$ and the $\phi$ field in the ${\tilde L} H_u$ direction of the slepton and Higgs doublets start together coherent evolution after the inflation with right-handed neutrino mass $M_N$ smaller than the Hubble parameter of inflation. Then, after some period the motion of ${\tilde N}$ and $\phi$ is drastically changed by the cross coupling $M_N h_\nu {\tilde N}^* \phi \phi$ from the $M_N N N$ and $h_\nu N L H_u$ terms, and the significant asymmetries of ${\tilde N}$ and ${\tilde L}$ are generated. The ${\tilde L}$ asymmetry is fixed later by the thermal effect as the lepton number asymmetry for baryogenesis, while the ${\tilde N}$ asymmetry disappears through the decays ${\tilde N} \to {\bar L} {\bar{\tilde H}}_u, {\tilde L} H_u$ with almost the same rate but opposite final lepton numbers.Comment: 4pages, 1 figure; submitted to Physical Review D. The renormalization group effects were include

Affleck-Dine baryogenesis with modulated reheating

Modulated reheating scenario is one of the most attractive models that predict possible detections of not only the primordial non-Gaussianity but also the tensor fluctuation through future CMB observations such as the Planck satellite, the PolarBeaR and the LiteBIRD satellite experiments. We study the baryonic-isocurvature fluctuations in the Affleck-Dine baryogenesis with the modulated reheating scenario. We show that the Affleck-Dine baryogenesis can be consistent with the modulated reheating scenario with respect to the current observational constraint on the baryonic-isocurvature fluctuations.Comment: 7 page

Flavour Issues in Leptogenesis

We study the impact of flavour in thermal leptogenesis, including the quantum oscillations of the asymmetries in lepton flavour space. In the Boltzmann equations we find different numerical factors and additional terms which can affect the results significantly. The upper bound on the CP asymmetry in a specific flavour is weaker than the bound on the sum. This suggests that -- when flavour dynamics is included -- there is no model-independent limit on the light neutrino mass scale,and that the lower bound on the reheat temperature is relaxed by a factor ~ (3 - 10).Comment: 19 pages, corrected equations for flavour oscillation

Leptogenesis from a sneutrino condensate revisited

We re--examine leptogenesis from a right--handed sneutrino condensate, paying special attention to the $B-$term associated with the see--saw Majorana mass. This term generates a lepton asymmetry in the condensate whose time average vanishes. However, a net asymmetry will result if the sneutrino lifetime is not much longer than the period of oscillations. Supersymmetry breaking by thermal effects then yields a lepton asymmetry in the standard model sector after the condensate decays. We explore different possibilities by taking account of both the low--energy and Hubble $B-$terms. It will be shown that the desired baryon asymmetry of the Universe can be obtained for a wide range of Majorana mass.Comment: 17 revtex pages, 3 figures, 1 table. Slightly modified and references added. Final version accepted for publication in Phys. Rev.

Beyond the standard seesaw: neutrino masses from Kahler operators and broken supersymmetry

We investigate supersymmetric scenarios in which neutrino masses are generated by effective d=6 operators in the Kahler potential, rather than by the standard d=5 superpotential operator. First, we discuss some general features of such effective operators, also including SUSY-breaking insertions, and compute the relevant renormalization group equations. Contributions to neutrino masses arise at low energy both at the tree level and through finite threshold corrections. In the second part we present simple explicit realizations in which those Kahler operators arise by integrating out heavy SU(2)_W triplets, as in the type II seesaw. Distinct scenarios emerge, depending on the mechanism and the scale of SUSY-breaking mediation. In particular, we propose an appealing and economical picture in which the heavy seesaw mediators are also messengers of SUSY breaking. In this case, strong correlations exist among neutrino parameters, sparticle and Higgs masses, as well as lepton flavour violating processes. Hence, this scenario can be tested at high-energy colliders, such as the LHC, and at lower energy experiments that measure neutrino parameters or search for rare lepton decays.Comment: LaTeX, 34 pages; some corrections in Section