Related papers: Proton Decay and the Planck Scale
A broad overview of the current status of proton stability in unified models of particle interactions is given which includes non - supersymmetric unification, SUSY and SUGRA unified models, unification based on extra dimensions, and…
Supersymmetric extensions of the Standard Model with small R-parity and lepton number violating couplings are naturally consistent with primordial nucleosynthesis, thermal leptogenesis and gravitino dark matter. We consider supergravity…
The Minimal Supersymmetric Standard Model (MSSM) is plagued by two major fine-tuning problems: the mu-problem and the proton decay problem. We present a simultaneous solution to both problems within the framework of a U(1)'-extended MSSM…
We investigate the predictions for various nucleon decay rates and their ratios in non-supersymmetric SU(5) Grand Unified Theories (GUTs) where the masses of the third and second family down-type quarks and charged leptons each stem…
We study the flavour aspects of proton lifetime estimates in simple Grand unified models paying particular attention to their inherent fragility due to the notorious lack of control of some of the key parameters governing the relevant…
A minimal renormalizable SUSY SO(10) model with B-L symmetry broken by {\bf 126} Higgs field has recently been shown to predict all neutrino mixings and the ratio $\Delta m^2_{\odot}/\Delta m^2_A$ in agreement with observations. Unlike…
The existence of a fundamental ultraviolet scale, such as the Planck scale, may lead to modifications of the dispersion relations for particles at high energies, in some scenarios of quantum gravity. We apply effective field theory to this…
A new supersymmetric standard model based on N=1 supergravity is constructed, aiming at natural explanation for the proton stability without invoking an ad hoc discrete symmetry through R parity. The proton is protected from decay by an…
We consider the proton decay in supersymmetric models with a gravitino or axino lighter than the proton. This consideration leads to a stringent limit on the R parity and B violating Yukawa coupling of the superpotential operator U^c_i…
I investigate the role of nonrenormalizable terms, up to order N=8, in a superstring derived standard--like model. I argue that nonrenormalizable terms restrict the gauge symmetry, at the Planck scale, to be $SU(3)\times SU(2)\times…
Proton decay via d=5 operators is excluded by now not only in the framework of SUSY SU(5) but also its extensions like SUSY SO(10) are on the verge of being inconsistent with d=5 decays. It is reasonable therefore to suppress, e.g. by a…
We analyse the sensitivity of all experimentally observable asymmetries and energy distributions for the neutron beta-decay with a polarised neutron and unpolarised decay proton and electron and the lifetime of the neutron to contributions…
Supersymmetric standard model (MSSM) has two sources of rapid proton decay: (i) R-parity breaking terms and (ii) higher dimensional Planck induced B-violating terms; its extensions to include neutrino masses via the type I seesaw mechanism…
We investigate in detail the predictions coming from the d=4 operators for proton decay. We find the most general constraints for the R-parity violating couplings coming from proton decay, taking into account all fermion mixing and in…
We construct three flipped SU(5) X U(1)_X models from F-theory, and consider two such models from free fermionic string model building. To achieve the decoupling scenario in F-theory models and the string-scale gauge coupling unification in…
The standard cold dark matter cosmological model, while successful in explaining the observed large scale structure of the Universe, tends to overpredict structure on small scales. It has been proposed this problem may be alleviated in a…
We study a ${U(1)}_R$ symmetric extenstion of supersymmetric standard model with supersymmetry breaking in the visible as well as hidden sectors. Specifically we study ${U(1)}_R$ breaking effects parametrized by the gravitino mass. A…
The nucleon decay is a significant phenomenon to verify grand unified theories (GUTs). For the precise prediction of the nucleon lifetime induced by the gauge bosons associated with the unified gauge group, it is important to include the…
In supergravity, effective superpotential relevant to dimension five operators on proton decay processes also leads to supersymmetry breaking terms among sfermions, dimension four operators. These dimension four operators induce the…
Conventionally we collect electron and up/down-quarks (u,d)+(nu_e,e) to form unified generations, and collect the left-handed and the right-handed fermions of the same flavors (nu_e,e)+e^c. We can alternatively have a contorted multiplet,…