Related papers: Perturbativity in the seesaw mechanism
We show that the type-I seesaw, responsible for generating the light neutrino mass, itself is capable of accommodating one of the three right handed neutrinos as a freeze-in type of dark matter (DM) where the required smallness of the…
An alternative to the conventional see-saw mechanism is proposed to explain the origin of small neutrino masses in supersymmetric theories. The masses and couplings of the right-handed neutrino field are suppressed by supersymmetry…
We estimate the magnitude of Lepton Flavour Violation (LFV) from the phase of the neutrino Yukawa matrix. In the minimal supersymmetric standard model with right-handed neutrinos, the LFV processes l_i \to l_j \gamma can appear through the…
In this paper, we study the phenomenology of right-handed neutrino isosinglets. We consider the general situation where the neutrino masses are not necessarily given by $m_D^2/M$, where $m_D$ and $M$ are the Dirac and Majorana mass terms…
We give a new mechanism for generating very small, and almost degenerate, neutrino masses, without resorting to the see-saw mechanism or unnatural small Yukawa couplings. It requires the existence of at least 4 families with an almost…
The seesaw mechanism provides a simple explanation for the lightness of the known neutrinos. Under the standard assumption of a weak scale Dirac mass and a heavy sterile Majorana scale the neutrino mass is naturally suppressed below the…
We study the inverse seesaw mechanism for neutrino masses and phenomenological consequences in the context of conformal electro-weak symmetry breaking. The main difference to the usual case is that all explicit fermion mass terms including…
The measured $B$-meson semi-leptonic branching ratios $R_{D}$ and $R_{D^*}$ have long-standing deviations between theory and experiment. We introduce a model which explains both anomalies through a single interaction by introducing a…
We assume the universal Yukawa coupling (democratic mass matrix) with small violations for quarks, charged leptons and neutrinos masses. We could reproduce the mass hierarchy for quark masses and V_{CKM} matrix elements precisely. We adopt…
A solution to the problem of the origin of matter in the universe can be reasonably searched within extensions of the standard model that also explain neutrino masses and mixing. Models embedding the minimal seesaw mechanism can explain the…
Unlike the standard model where neutrino masses can be made arbitrarily small, we find in the minimal left-right symmetric model that Dirac type Yukawa coupling $h_D \sim 10^{-4.2}$ for $\nu_\tau$ is generated from charged fermion Yukawa…
In the context of a minimal extension of the Standard Model with three extra heavy right-handed neutrinos, we propose a model for neutrino masses and mixing based on the hipothesis of a complete alignment of the lepton mass matrices in…
By introducing three right-handed neutrino singlets, the popular canonical seesaw mechanism is able to simultaneously explain the tiny masses of Majorana neutrinos and the baryon asymmetry of the Universe. In this paper, we provide an…
We consider the type I see-saw model with two right-handed neutrinos and a normal neutrino mass hierarchy and impose a zero coupling between the right-handed neutrino mainly responsible for the atmospheric neutrino mass and the electron…
Various lepton-flavor violating (LFV) processes in the supersymmetric standard model with right-handed neutrino supermultiplets are investigated in detail. It is shown that large LFV rates are obtained when $\tan \beta $ is large. In the…
The presence of the triplet $\Delta_{L}$ in left-right symmetric theories leads to type-II see-saw mechanism for the neutrino masses. In these models, assuming a normal mass hierarchy for the heavy Majorana neutrinos, we derive a lower…
If an exact $\mu\leftrightarrow \tau$ symmetry is the explanation of the maximal atmospheric neutrino mixing angle, it has interesting implications for origin of matter via leptogenesis in models where small neutrino masses arise via the…
We study the non-Hermitian extension of the Lagrangian of the Standard Model extended by singlet right-handed heavy neutrinos. The Yukawa coupling matrices comprise of hermitian and non-hermitian components and the neutrino mass eigenvalues…
We propose a radiative seesaw model in alternative left-right model without any bidoublet scalar fields, in which all the fermion masses in the standard model are generated through a canonical seesaw mechanism at the tree level. On the…
It is pointed out that if a neutrino mass matrix for right-handed neutrinos in seesaw mechanism has mu -tau symmetry and total lepton number L_{e}+L_{\mu }+L_{\tau} remains constant (not zero), exact tribimaximal neutrino mixing in this…