Inflation from a No-scale supersymmetric $SU(4{)}_c\times SU(2{)}_L\times SU(2{)}_R$ model

Abstract

We study inflation in a supersymmetric Pati-Salam model driven by a potential generated in the context of no-scale supergravity. The Pati-Salam gauge group $SU(4{)}_c\times SU(2{)}_L\times SU(2{)}_R$ , is supplemented with a $Z_2$ symmetry. Spontaneous breaking via the $SU(4)$ adjoint leads to the left-right symmetric group. Then the $SU(2{)}_R$ breaks at an intermediate scale and the inflaton is a combination of the neutral components of the $SU(2{)}_R$ doublets. We discuss various limits of the parameter space and we show that consistent solutions with the cosmological data for the a spectral index $n_s$ and the tensor-to-scalar ratio r are found for a wide range of the parameter space of the model. Regarding the latter, which is a canonical measure of primordial gravity waves, we find that $r\sim 10^{-3}-10^{-2}$. An alternative possibility where the adjoint scalar field $S$ has the role of the inflaton is also discussed.

Comments: 23 Pages , 20 figures and 1 table