Arunansu Sil

We explore a realistic supersymmetric SU(2)L × SU(2)R × U(1) B - L model spontaneously broken at around 1012GeV. The presence of D- and F-flat directions gives rise to TeV mass doubly charged particles which can be found at the LHC. We implement TeV scale leptogenesis and employing both type I and II seesaw, the three light neutrinos are partially degenerate with masses in the 0.02-0.1 eV range. The effective mass parameter for neutrinoless double beta decay is 0.03-0.05 eV. We also find the interesting relation tan 2θ13 ≃sin 2θ12/tan 2θ23(Δm⊙2/Δmatm2) ≲ 0.02.

We present a leptogenesis scenario through the decay of heavy triplets following smooth hybrid inflation within a moderate extension of the left-right supersymmetric gauge group SU(2)L × SU(2)R × U(1)B-L. Baryon number conservation and the solution of the μ-problem are provided by additional symmetries. All the right handed neutrinos are heavier than inflatons. Then we have studied neutrino mass matrix generated by the triplet VEVs having the parameters constrained by leptogenesis and inflation scenario and found that the production of the required lepton asymmetry of the universe is not only right enough to be consistent with the neutrino mass and mixing angles predicted by the recent data but also can provide an estimate of b - τ unification in the context of a minimal susy SO(10) model.

We show that a standard model gauge singlet fermion field, with mass of order keV or larger, and involved in the inverse seesaw mechanism of light neutrino mass generation, can be a good warm dark matter candidate. Our framework is based on B-L extension of the Standard Model. The construction ensures the absence of any mixing between active neutrinos and the aforementioned dark matter field. This circumvents the usual constraints on the mass of warm dark matter imposed by X-ray observations. We show that over-abundance of thermally produced warm dark matter (which nevertheless do not reach chemical equilibrium) can be reduced to an acceptable range in the presence of a moduli field decaying into radiation --- though only when the reheat temperature is low enough. Our warm dark matter candidate can also be produced directly from the decay of the moduli field during reheating. In this case, obtaining the right amount of relic abundance, while keeping the reheat temperature high enough as to be consistent with Big Bang nucleosynthesis bounds, places constraints on the branching ratio for the decay of the moduli field into dark matter.

We consider a smooth hybrid inflation scenario based on a supersymmetric SU(2)_L x SU(2)_R x U(1)_B-L model. The Higgs triplets involved in the model play a key role in inflation as well as in explaining the observed baryon asymmetry of the universe. We show that the baryon asymmetry can originate via non-thermal triplet leptogenesis from the decay of SU(2)_L triplets, whose tiny vacuum expectation values also provide masses for the light neutrinos.

We propose a scenario for realizing inflation in the framework of supersymmetric B-L extension of the standard model. We find that one of the associated right-handed sneutrinos (the superpartner of the standard model singlet fermion) can provide a new nontrivial inflationary trajectory at tree level (therefore breaking B-L during inflation). As soon as the inflation ends, the right-handed sneutrino falls into the supersymmetric vacuum, with a vanishing vacuum expectation value, so that B-L symmetry is restored. In this class of models, the B-L gauge symmetry will be radiatively broken at a TeV scale and light neutrino masses are generated through the inverse seesaw mechanism.

We present a leptogenesis scenario through the decay of heavy triplets following smooth hybrid inflation within a moderate extension of the left-right supersymmetric gauge group SU(2)L × SU(2)R × U(1)B-L. Baryon number conservation and the solution of the mu-problem are provided by additional symmetries. All the right handed neutrinos are heavier than inflatons. Then we have studied neutrino mass matrix generated by the triplet VEVs having the parameters constrained by leptogenesis and inflation scenario and found that the production of the required lepton asymmetry of the universe is not only right enough to be consistent with the neutrino mass and mixing angles predicted by the recent data but also can provide an estimate of b - tau unification in the context of a minimal susy SO(10) model.

ABSTRACT We have shown that inflation in the supersymmetric B - L extension of the Standard Model can be realized where one of the associated right-handed sneutrinos can provide a non-trivial inflationary trajectory at tree level (hence breaking B - L during inflation). As soon as the inflation ends, the right-handed sneutrino falls into the supersymmetric vacuum, with a vanishing vacuum expectation value, so that B - L symmetry is restored. The B - L gauge symmetry will be radiatively broken at a TeV scale and light neutrino masses are generated through the inverse seesaw mechanism.