Related papers: Generation Structure and Proton Decay Problem
The Standard Model has three generations of fermions and although it does not contain any explicit reason for this, the existence of additional generations is now very constrained by experiment. Present measurements are saturating…
We consider the possibility that the $\tau$ decay puzzle, if it is confirmed in future experiments, is a consequence of the Kobayashi-Maskawa mixing in the leptonic sector
In left-right symmetric seesaw models an eight-fold degeneracy among the right-handed neutrino mass matrices is known to exist. We use stability and viability of leptogenesis as criteria in order to discriminate among the degenerate…
A Hexad Preon model where leptons, quarks and W Z bosons are composite is proposed. Six Hexad Preons transform under $U(3)\otimes U(3)$ local gauge theory which is identified with $U(1)_Q\otimes SU(3)_C\otimes SU(3)_f\otimes U(1)_w$. All…
We present a comprehensive study of an extended SU(5) grand unified theory (GUT) that incorporates a 45-dimensional Higgs representation to address the shortcomings of the minimal SU(5) GUT, such as the inability to generate realistic…
The existence of R-parity in supersymmetric models can be naturally explained as being a discrete subgroup of gauged baryon minus lepton number (B-L). The most minimal supersymmetric B-L model triggers spontaneous R-parity violation, while…
We propose a mechanism for sufficient suppression of dimension-5 operators for proton decay in a supersymmetric SO(10) model. This mechanism is analogue to the double seesaw mechanism in studying neutrino masses. Only an intermediate VEV…
We assess proton decay signatures in the simplest viable $SU(5)$ model with regard to constraints on parameters governing the Standard Model fermion mass spectrum. Experimental signals for all eight two-body proton decay processes result…
We explore proton decay in a class of realistic supersymmetric flipped $SU(5)$ models supplemented by a $U(1)_R$ symmetry which plays an essential role in implementing hybrid inflation. Two distinct neutrino mass models, based on inverse…
We advocate the idea that proton decay may probe physics at the Planck scale instead of the GUT scale. This is possible because supersymmetric theories have dimension-5 operators that can induce proton decay at dangerous rates, even with…
A search for new particles has been conducted using events with two high transverse momentum (pt) tau leptons that decay hadronically, at least two high-pt jets, and missing transverse energy from the tau lepton decays. The analysis is…
We study proton decay in a supersymmetric {\sf SO(10)} gauge theory in six dimensions compactified on an orbifold. The dimension-5 proton decay operators are forbidden by R-symmetry, whereas the dimension-6 operators are enhanced due to the…
We present what we believe are the first specific string (D-brane) constructions whose low-energy limit yields just a three generation $SU(3)\times SU(2)\times U(1)$ standard model with no extra fermions nor U(1)'s (without any further…
I review the theoretical and experimental status of proton decay theory and experiment. Regarding theory, I focus mostly, but not only, on grand unification. I discuss only the minimal, well established SU(5) and SO(10) models, both…
We present a comprehensive analysis of a supersymmetric $SO(10)$ Grand Unified Theory, which is broken to the Standard Model via the breaking of two intermediate symmetries. The spontaneous breaking of the first intermediate symmetry,…
We demonstrate that a phenomenologically viable four-dimensional grand unified theory with no proton decay can be constructed. This is done in the framework of the minimal non-supersymmetric SU(5) GUT by introducing new representations and…
We show that in a class of minimal supersymmetric SO(10) models which have been found to be quite successful in predicting neutrino mixings, all proton decay modes can be suppressed by a particular choice of Yukawa textures. This…
We consider phenomenological aspects of a natural class of Standard Model-like supersymmetric F-theory vacua realized through flux breaking of rigid $E_7$ gauge factors. Three generations of Standard Model matter are realized in many of…
A model is proposed in which quarks, leptons and perhaps gauge bosons are composites of magnetically charged rishons T(q=1/3) and V(q=0) with magnetic charges g=(1,2,-3)g0. Structural formulas of composite particles and their interactions…
A search for pair-produced scalar and vector leptoquarks decaying into quarks and leptons of different generations is presented. It uses the full LHC Run 2 (2015-2018) data set of 139 fb$^{-1}$ collected with the ATLAS detector in…