Higgs inflation from new Kähler potential

Abstract

We introduce a new class of models of Higgs inflation using the superconformal approach to supergravity by modifying the K$\ddot{a}$hler geometry. Using such a mechanism, we construct a phenomenological functional form of a new K$\ddot{a}$hler potential. From this we construct various types of models which are characterized by a superconformal symmetry breaking parameter $χ$, and depending on the numerical values of $χ$ we classify all of the proposed models into three categories. Models with minimal coupling are identified by $χ=\pm\frac{2}{3}$ branch which are made up of shift symmetry preserving flat directions. We also propose various other models by introducing a non-minimal coupling of the inflaton field to gravity described by $χ\neq\frac{2}{3}$ branch. We employ all these proposed models to study the inflationary paradigm by estimating the major cosmological observables and confront them with recent observational data from WMAP9 along with other complementary data sets, as well as independently with PLANCK. We also mention an allowed range of non-minimal couplings and the {\it Yukawa} type of couplings appearing in the proposed models used for cosmological parameter estimation.