We consider models built on $AdS_5otimes S^5/Gamma$ orbifold compactifications of the type $IIB$ superstring, where $Gamma$ is the abelian group $Z_n$. An attractive three family $mathcal{N}=0$ SUSY model is found for $n=7$ that is a modified Pati--Salam Model which reduced to the Standard Model after symmetry breaking.
We provide what we believe is the minimal three family ${cal N} = 1$ SUSY and conformal Pati-Salam Model from type IIB superstring theory. This $Z_3$ orbifolded AdS$otimes S^5$ model has long lived protons and has potential phenomenological consequences for LHC.
In this talk I discuss a supersymmetric Pati-Salam model of fermion masses and mixing angles which fits low energy data. The model is then extended to include an inflationary sector which is shown to be consistent with Bicep2-Keck-Planck data. The en
ergy scale during inflation is associated with the PS symmetry breaking scale. Finally, the model is shown to be consistent with the observed baryon-to-entropy ratio necessary for Big Bang Nucleosynthesis. It turns out that only the heaviest right-handed neutrino decays produce the correct sign of the baryon-to-entropy ratio. Nevertheless, we obtain the observed value due to the process of instant preheating.
Composite Higgs models can be extended to the Planck scale by means of the partially unified partial compositeness (PUPC) framework. We present in detail the Techni-Pati-Salam model, based on a renormalizable gauge theory $SU(8)_{PS}times SU(2)_Ltime
s SU(2)_R$. We demonstrate that masses and mixings for all generations of standard model fermions can be obtained via partial compositeness at low energy, with four-fermion operators mediated by either heavy gauge bosons or scalars. The strong dynamics is predicted to be that of a confining $Sp(4)_{rm HC}$ gauge group, with hyper-fermions in the fundamental and two-index anti-symmetric representations, with fixed multiplicities. This motivates for Lattice studies of the Infra-Red near-conformal walking phase, with results that may validate or rule out the model. This is the first complete and realistic attempt at providing an Ultra-Violet completion for composite Higgs models with top partial compositeness. In the baryon-number conserving vacuum, the theory also predicts a Dark Matter candidate, with mass in the few TeV range, protected by semi-integer baryon number.
We implement the mechanism of non-thermal leptogenesis in the framework of an inflationary model based on a supersymmetric (SUSY) Pati-Salam Grand Unified Theory (GUT). In particular, we show that inflation is driven by a quartic potential associated
with the Higgs fields involved in the spontaneous GUT symmetry breaking, in the presence of a non-minimal coupling of the inflaton field to gravity. The inflationary model relies on renormalizable superpotential terms and does not lead to overproduction of magnetic monopoles. It is largely independent of one-loop radiative corrections, and it can be consistent with current observational data on the inflationary observables, with the GUT symmetry breaking scale assuming its SUSY value. Non-thermal leptogenesis is realized by the out-of-equilibrium decay of the two lightest right-handed (RH) neutrinos, which are produced by the inflaton decay. Confronting our scenario with the current observational data on light neutrinos, the GUT prediction for the heaviest Dirac neutrino mass, the baryon asymmetry of the universe and the gravitino limit on the reheating temperature, we constrain the masses of the RH neutrinos in the range (10^10-10^15) GeV and the Dirac neutrino masses of the two first generations to values between 0.1 and 20 GeV.
Lepton number as a fourth color is the intriguing theoretical idea of the famous Pati-Salam (PS) model. While in conventional PS models, the symmetry breaking scale and the mass of the resulting vector leptoquark are stringently constrained by $K_Lto
mu e$ and $Ktopimu e$, the scale can be lowered to a few TeV by adding vector-like fermions. Furthermore, in this case, the intriguing hints for lepton flavour universality violation in $bto smu^+mu^-$ and $bto ctau u$ processes can be addressed. Such a setup is naturally achieved by implementing the PS gauge group in the five-dimensional Randall-Sundrum background. The PS symmetry is broken by boundary conditions on the fifth dimension and the resulting massive vector leptoquark automatically has the same mass scale as the vector-like fermions and all other resonances. We consider the phenomenology of this model in the context of the hints for lepton flavour universality violation in semileptonic $B$ decays. Assuming flavour alignment in the down sector we find that in $bto sell^+ell^-$ transitions the observed deviations from the SM predictions (including $R(K)$ and $R(K^*)$) can be explained with natural values for the free parameters of the model. Even though we find sizable effects in $R(D)$, $R(D^*)$ and $R(J/Psi)$ one cannot account for the current central values in the constrained setup of our minimal model due to the stringent constraints from $D-bar D$ mixing and $tauto 3mu$.