$\alpha$-attractors from supersymmetry breaking

Abstract

We construct new models of inflation and spontaneous supersymmetry breaking in de Sitter vacuum, with a single chiral superfield, where inflaton is the superpartner of the goldstino. Our approach is based on hyperbolic Kähler geometry, and a gauged (non-axionic) $U(1{)}_R$ symmetry rotating the chiral scalar field by a phase. The $U(1{)}_R$ gauge field combines with the angular component of the chiral scalar to form a massive vector, and single-field inflation is driven by the radial part of the scalar. We find that in a certain parameter range they can be approximated by simplest Starobinsky-like (E-model) $\alpha$-attractors, thus predicting $n_s$ and $r$ within $1\sigma$ CMB constraints. Supersymmetry (and $R$-symmetry) is broken at a high scale with the gravitino mass $m_{3/2}\gtrsim 10^{14}$ GeV, and the fermionic sector also includes a heavy spin-$1/2$ field. In all the considered cases the inflaton is the lightest field of the model.

Comments: 26 pages, 9 figures, 3 tables. v2: updated version accepted to EPJC