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 neutrinos and the triplet to the lepton asymmetry are proportional to their respective contributions to the neutrino mass matrix. A consequence of the triplet contribution to the lepton asymmetry is that there is no more upper bound on the neutrino masses from leptogenesis due to the fact that the neutrino mass constraints do not necessarily induce asymmetry washout effects. We also show how such a triplet leptogenesis mechanism may emerge naturally in the framework of the left–right symmetric theories, such as Pati–Salam or SO(10).
We show that the minimal renormalizable supersymmetric SO(10) GUT with the usual three generations of spinors has a Higgs sector consisting only of a “light” 10 dimensional and “heavy” 126, 126 and ...210 supermultiplets. The theory has only two sets of Yukawa couplings with fifteen real parameters and ten real parameters in the Higgs superpotential. It accounts correctly for all the fermion masses and mixings, neutrinos included. The theory predicts at low energies the MSSM with exact R-parity. It is arguably the minimal consistent supersymmetric grand unified theory.
Planck-scale physics and neutrino masses AKHMEDOV, E. K; BEREZHIANI, Z. G; SENJANOVIC, G
Physical review letters,
11/1992, Letnik:
69, Številka:
21
Journal Article
Recenzirano
Odprti dostop
We discuss gravitationally induced masses and mass splittings of Majorana, Zeldovich-Konopinski-Mahmoud, and Dirac neutrinos. Among other implications, these effects can provide a solution of the ...solar neutrino puzzle. In particular, we show how this may work in the 17 keV neutrino picture. (Author)
Strong CP problem and parity BARR, S. M; DARWIN CHANG; GORAN SENJANOVIC
Physical review letters,
11/1991, Letnik:
67, Številka:
20
Journal Article
Recenzirano
We analyze the possibility of solving the strong {ital CP} problem by imposing parity symmetry. Some simple realizations of such a scheme are given and interesting phenomenological and cosmological ...consequences are discussed.
Neutrino and charged fermion masses provide important constraints on grand unified theories. We illustrate this by focusing on a renormalizable, supersymmetric SO(10) theory proposed long ago, that ...recently attracted great interest in view of its minimality. We show how the nature of the light Higgs, which depends on the GUT scale fields, gets reflected on the precise predictions for fermion masses and mixings. We exemplify this on the case of dominant type II see-saw, which gets severely constrained and is likely to fail.
We investigate the possibility of low-scale leptogenesis in the minimal supersymmetric standard model extended with right-handed (s)neutrinos. We demonstrate that successful leptogenesis can be ...easily achieved at a scale as low as approximately TeV where lepton number and CP violation comes from soft supersymmetry breaking terms. The scenario is shown to be compatible with neutrino masses data.
We revive Witten's mechanism for the radiative seesaw induced neutrino masses in SO(10) grand unified theory. We propose its extension to charged fermion masses as a possible cure for wrong tree ...level mass relations. We offer two simple realizations that can produce a realistic fermionic spectrum. The first one requires two 10-dimensional Higgses in the Yukawa sector and utilizes radiative effects for charged fermion masses. The second one trades one 10- for a 120-dimensional Higgs and leads to the SO(10) theory with less parameters in the Yukawa sector. The mechanism works only if supersymmetry is broken at the GUT scale while gauginos and higgsinos remain at TeV. This provides a strong rationale for the so-called split supersymmetry.
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