Abstract
We have proposed recently a framework for inflation driven by supersymmetry breaking with the inflaton being a superpartner of the goldstino, that avoids the main problems of supergravity inflation, allowing for: naturally small slow-roll parameters, small field initial conditions, absence of a (pseudo)scalar companion of the inflaton, and a nearby minimum with tuneable cosmological constant. It contains a chiral multiplet charged under a gauged R-symmetry which is restored at the maximum of the scalar potential with a plateau where inflation takes place. The effective field theory relies on two phenomenological parameters corresponding to corrections to the Kähler potential up to second order around the origin. The first guarantees the maximum at the origin and the second allows the tuning of the vacuum energy between the F- and D-term contributions. Here, we provide a microscopic model leading to the required effective theory. It is a Fayet–Iliopoulos model with two charged chiral multiplets under a second mathrm{U}(1) R-symmetry coupled to supergravity. In the Brout–Englert–Higgs phase of this mathrm{U}(1), the gauge field becomes massive and can be integrated out in the limit of small supersymmetry breaking scale. In this work, we perform this integration and we show that there is a region of parameter space where the effective supergravity realises our proposal of small field inflation from supersymmetry breaking consistently with observations and with a minimum of tuneable energy that can describe the present phase of our Universe.
Highlights
We have proposed recently a framework for inflation driven by supersymmetry breaking with the inflaton being a superpartner of the goldstino, that avoids the main problems of supergravity inflation, allowing for: naturally small slow-roll parameters, small field initial conditions, absence of ascalar companion of the inflaton, and a nearby minimum with tuneable cosmological constant
In the Brout–Englert–Higgs phase of this U(1), the gauge field becomes massive and can be integrated out in the limit of small supersymmetry breaking scale. We perform this integration and we show that there is a region of parameter space where the effective supergravity realises our proposal of small field inflation from supersymmetry breaking consistently with observations and with a minimum of tuneable energy that can describe the present phase of our Universe
There is a region of parameter space, when the FI parameter is large compared to the electron mass, where the U(1) is broken and supersymmetry breaking is dominated by an F-term but is still small compared to the U(1) mass
Summary
This section reviews a class of models studied recently by the present authors [1], in which the inflaton is identified with the scalar superpartner of the goldstino in the presence of a gauged R-symmetry. The model allows the presence of a realistic minimum with an infinitesimal positive vacuum energy This is realised due to a cancellation between the F- and D-term contributions to the scalar potential, without affecting the properties of the inflationary plateau. We will summarise the main features of models of case 1 that we consider in this work, where inflation occurs near the maximum of the scalar potential where R-symmetry is restored. We consider the case where the F-term potential is dominant by setting y to be very small so that y can be neglected Taking this into account, let us find some constraints on the coefficient A of the quadratic term of the Kähler potential. We explore a microscopic model that can generate the coefficient A satisfying the requirement (2.16)
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