Related papers: A Note on Proton Stability in the Standard Model
We propose two supersymmetric Standard Models (SMs) with decaying and stable dark matter (DM) particles. To explain the SM fermion masses and mixings and have a heavy decay DM particle S, we consider the Froggatt-Nielsen mechanism by…
The straightforward supersymmetrization of the Standard Model (SM) results in a phenomenologically inconsistent theory in which Baryon number ($B$) and Lepton number ($L$) are violated by dimension 4 operators, inducing fast proton decay.…
A simple extension of the minimal supersymmetric standard model in which baryon and lepton numbers are local gauge symmetries spontaneously broken at the supersymmetry scale is reported. This theory provides a natural explanation for proton…
We show that more than two generations of quarks and leptons are required to have an anomaly free discrete R-symmetry larger than R-parity, provided that the supersymmetric Standard Model can be minimally embedded into a grand unified…
Grand unification, and its incarnation in the form of heterotic-string unification, are the only extensions of the Standard Model that are rooted in the structure of the Standard Model itself. In this context, it was proposed that the…
We propose a new possibility to realize simultaneously the sufficient proton stability and the interesting structure of neutrino mass matrix in superstring inspired $E_6$ models. In this model the leptons and Higgs fields are assigned to a…
Issues of proton decay are examined in supersymmetric standard model with U(1) flavor symmetry. Dimension five proton-decay operators which arise generically are controlled by the flavor symmetry. We show that unlike the minimal…
In various supersymmetric extensions of the Standard Model there appear non-topological solitons due to the existence of U(1) global symmetries associated with Baryon and/or Lepton quantum numbers. Trilinear couplings (A-terms) in the…
Non-observation of proton decays as well as the smallness of the neutrino masses can naturally be explained by the accidental baryon and lepton number symmetry in the Standard Model, where the approximate symmetries are a consequence of the…
We consider proton stability based on E_6 inspired extra U(1) model with S_4 x Z_2 flavor symmetry. In this model, a long life time of proton is realized by the flavor symmetry in several ways. We classify the suppression mechanisms of…
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…
In most supersymmetric models the stability of the proton is ensured by invoking R-parity. A necessary ingredient to enforce R-parity is the possibility of distinguishing the lepton superfields from the Higgs ones. This is generally…
We demonstrate the existence of an extra nonanomalous U(1) gauge symmetry in a three-generation Pati-Salam model constructed with intersecting D6-branes in Type IIA string theory on a T^6/(Z_2 \times Z_2) orientifold. This extra U(1)…
We discuss proton decay in a recently proposed model of supersymmetric hybrid inflation based on the gauge symmetry $SU(4)_c \times SU(2)_L \times SU(2)_R$. A $U(1)\, R$ symmetry plays an essential role in realizing inflation as well as in…
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 introduce a natural origin of the Peccei-Quinn (PQ) symmetry with a sufficiently good precision. In the standard model, the baryon number symmetry U(1)_B arises accidentally due to the SU(3)_C color gauge symmetry, and it protects the…
We consider heterotic Calabi-Yau compactifications with S(U(4)xU(1)) background gauge fields. These models lead to gauge groups with an additional U(1) factor which, under certain conditions, can combine with hypercharge to a B-L symmetry.…
A unified model is constructed, based on flipped $SU(5)$ in which the proton is absolutely stable. The model requires the existence of new leptons with masses of order the weak scale. The possibility that the unification scale could be…
We discuss phenomenological implications of non-invertible selection rules in the framework of the supersymmetric standard model. We find that a remnant $\mathbb{Z}_2$ symmetry of fusion algebras which holds at all-loop order plays the role…
A moderate extension of the minimal supersymmetric standard model which includes a U(1)_(B-L) gauge group (B and L being the baryon and lepton number) and a Peccei-Quinn symmetry, U(1)_PQ, is presented. The hybrid inflationary scenario is…