Related papers: Gravitational Leptogenesis
We discuss the question of CP-violation in the effective Hamiltonian approach in models of leptogenesis through heavy right handed neutrino decays. We first formulate the problem in four component notation and then point out that before the…
The addition of gauge singlet fermions to the Standard Model Lagrangian renders the neutrinos massive and allows one to explain all that is experimentally known about neutrino masses and lepton mixing. At the same time, the gauge singlet…
The mechanism of gravitational baryogenesis, based on the CPT-violating gravitational interaction between the derivative of the Ricci scalar curvature and the baryon-number current, is investigated in the context of the Gauss-Bonnet…
We present a mechanism of leptogenesis based on the out-of-equilibrium decay of a scalar particle into heavy virtual Majorana neutrinos. This scheme presents many conceptual advantages over the conventional scenario of Fukugita and…
We consider a supersymmetric SU(4)$_c \times$SU(2)$_L \times$SU(2)$_R$ model with a minimal number of Higgs multiplets and Dirac and Majorana $CP$-violating phases in the neutrino flavor mixing matrix. The model incorporates the charged…
In this work we study a classically scale invariant extension of the Standard Model that can explain simultaneously dark matter and the baryon asymmetry in the universe. In our set-up we introduce a dark sector, namely a non-Abelian SU(2)…
We further study the previously proposed Ansatz, Tr(M)=0, for a prediagonal light Majorana type neutrino mass matrix. If CP violation is neglected this enables one to use the existing data on squared mass differences to estimate (up to a…
The lepton asymmetry created in the out-of-equilibrium decay of a heavy Majorana neutrino can generate the cosmological baryon asymmetry when processed through fast anomalous electroweak reactions. In this work I examine this process under…
We investigate a model on an extra dimension $S^1$ where plenty of effective boundary points described by point interactions (zero-thickness branes) are arranged. After suitably selecting the conditions on these points for each type of…
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…
Models for Majorana neutrino masses can be classified according to the level in perturbation theory at which the effective dimension five operator $LLHH$ is realized. The possibilities range from the tree-level up to the three-loop level…
We investigate a minimal extension of the Leptogenesis framework that simultaneously explains the observed baryon asymmetry and dark matter (DM) abundance through the decay of a heavy Majorana neutrino. In this scenario, CP violation arises…
We propose a simple extension of the standard model by adding a fourth generation vector-like lepton doublet and show that if the fourth neutrino is a massive pseudo-Dirac fermion with mass in the few hundred GeV range and mass splitting of…
Supersymmetry offers a cold dark matter candidate, provided that lepton number is {\em not violated by an odd number of units}. On the other hand, lepton number violation by even (two) units gives us an attractive mechanism of neutrino mass…
We propose that the observed matter-antimatter asymmetry can be naturally produced as a byproduct of axion-driven slow-roll inflation by coupling the axion to standard-model neutrinos. We assume that GUT scale right-handed neutrinos are…
We study leptogenesis in two seesaw models where maximal atmospheric neutrino mixing and $U_{e3} = 0$ result from symmetries. Salient features of those models are the existence of three Higgs doublets and a twofold degeneracy of the…
We analyse in detail the phenomenological implications for lepton masses and mixing derived by the breaking of the discrete symmetries $A_5 \times CP$ into the subgroups $Z_2 \times CP$ in the neutrino sector and $Z_5$ in the charged lepton…
We study the prospects of thermal leptogenesis in the framework of the minimal flipped $SU(5)$ unified model in which the RH neutrino mass scale emerges as a two-loop effect. Despite its strong suppression with respect to the unification…
The minimal flipped $SU(5)$ unification with the right-handed neutrino Majorana mass scale generated as a two-loop effect is arguably one of the most constrained models of perturbative baryon and lepton number violation currently on the…
If the present or upcoming searches for neutrinoless double beta decay give a positive result, the Majorana nature of massive neutrinos will be established. From the determination of the value of the effective Majorana mass parameter |<m>|,…