Related papers: Leptogenesis in fast expanding Universe
Leptogenesis is usually realized through decays of heavy particles. In this article we consider another possibility of generating a lepton asymmetry through annihilations of heavy particles. We demonstrate our idea with a realistic…
Scalar fields can play a dominant role in the dynamics of the Universe until shortly before nucleosynthesis. Examples are provided by domination by a kinetic mode of a scalar field, which may be both the inflaton and the late time…
The observed baryon asymmetry of the Universe is suitably created in thermal leptogenesis through the out-of-equilibrium decay of $N_1$, the lightest of the three heavy singlet neutral fermions which anchor the seesaw mechanism to obtain…
We study a seesaw-type extension of the Standard Model in which the symmetry group is enlarged by a global U(1). We introduce adequate scalar and fermion representations which naturally explain the smallness of neutrino masses. With the…
We revisit leptogenesis in the minimal non-supersymmetric type I see-saw mechanism with two right-handed (RH) neutrinos, including flavour effects and allowing both RH neutrinos N_1 and N_2 to contribute, rather than just the lightest RH…
We present the various leptogenesis scenarios which may occur if, in addition to the ordinary heavy right-handed neutrinos, there exists a heavy scalar SU(2)_L triplet coupled to leptons. We show that the contributions of the right-handed…
Instead of creating the observed baryon asymmetry of the universe by the decay of right-handed (RH) neutrinos to left-handed leptons, we propose to generate it dominantly by the decay of the RH neutrinos to RH leptons. This mechanism turns…
In supersymmetric models with lepton-number violation, hence also R-parity violation, it is easy to have realistic neutrino masses, but then leptogenesis becomes difficult to achieve. After explaining the general problems involved, we study…
In this paper we consider the possibility of neutrino mass varying during the evolution of the Universe and study its implications on leptogenesis. Specifically, we take the minimal seesaw model of neutrino masses and introduce a coupling…
We consider the mechanism of thermal leptogenesis at the TeV scale in the context of an extension of the Standard Model with 4 generations and the inclusion of four right-handed Majorana neutrinos. We obtain a value for the baryon asymmetry…
The lepton flavour violating charged lepton decays mu to e + gamma and thermal leptogenesis are analysed in the minimal supersymmetric standard model with see-saw mechanism of neutrino mass generation and soft supersymmetry breaking terms…
One of the major challenges in particle physics and cosmology is understanding why there is an asymmetry between matter and antimatter in the Universe. One possible explanation for this phenomenon is thermal leptogenesis, which involves the…
We consider thermal leptogenesis as the origin of the matter-antimatter asymmetry of the Universe. Some phenomenologically unpleasant features of the usual leptogenesis scenario are reviewed. We propose a minimal alternative, which makes…
We study the scenario of thermal leptogenesis in which the leptonic asymmetries are resonantly enhanced through the mixing of nearly degenerate heavy Majorana neutrinos that have mass differences comparable to their decay widths.…
We show that the leptogenesis is automatic within the supersymmetric standard model if there exist right-handed neutrinos with mass less than $H_{\it inf}$, the expansion rate during the inflation. Its scalar component grows during the…
We present a simple extension of the Standard Model with three right-handed neutrinos in a SUSY framework, with an additional U(1$)_\text{F}$ abelian flavor symmetry with a non standard leptonic charge $L_e-L_\mu-L_\tau$ for lepton doublets…
We study the consequence of a non-standard cosmological epoch in the early universe on the generation of baryon asymmetry through leptogenesis as well as dark matter abundance. We consider two different non-standard epochs: one where a…
In this talk we show how a natural neutrino mass hierarchy can follow from the type I see-saw mechanism, and a natural neutrino mass degeneracy from the type II see-saw mechanism, where the bi-large mixing angles can arise from either the…
It is shown that the type III seesaw mechanism proposed recently can have certain advantages over the conventional (or type I) seesaw mechanism for leptogenesis. In particular a resonant enhancement of leptogenesis via heavy quasi-Dirac…
Recently the ATLAS and CMS collaborations have reported evidence of a diphoton excess which may be interpreted as a pseudoscalar boson S with a mass around 750 GeV. To explain the diphoton excess, such a boson is coupled to the Standard…