Reheating processes after Starobinsky inflation in old-minimal supergravity

Abstract: We study reheating processes and its cosmological consequences in the Starobinsky model embedded in the old-minimal supergravity. First, we consider minimal coupling between the gravity and matter sectors in the higher curvature theory, and transform it to the equivalent standard supergravity coupled to additional matter superfields. We then discuss characteristic decay modes of the inflaton and the reheating temperature T_R. Considering a simple model of supersymmetry breaking sector, we estimate gravitino abundance from inflaton decay, and obtain limits on the masses of gravitino and supersymmetry breaking field. We find T_R ≃ 1.0 × 10⁹ GeV and the allowed range of gravitino mass as 10⁴ GeV ≲ m_3/2 ≲ 10⁵ GeV, assuming anomaly-induced decay into the gauge sector as the dominant decay channel.