Supergravity and two-field inflation effects in right-handed sneutrino-modified D-term inflation

Abstract

We extend previous work on the minimal D-term inflation model modified by right-handed (RH) sneutrino fields to include additional inflaton-sector supergravity corrections and two-field inflation effects. We show that supergravity corrections simultaneously allow ${n}_{s}$ to be within 3-year Wilkinson Microwave Anisotropy Probe limits and the cosmic string contribution to the cosmic microwave background (CMB) power spectrum to be less than 5%. For gauge coupling $g\ensuremath{\le}1$, the CMB contribution from cosmic strings is predicted to be at least 1% while the spectral index is predicted to be less than 0.968 for a CMB string contribution less than 5%. Treating the inflaton-RH sneutrino system as a two-field inflation model, we show that the time-dependence of the RH sneutrino field strongly modifies the single-field results for values of RH sneutrino mass ${m}_{\ensuremath{\Phi}}>0.1H$. The running spectral index is $\ensuremath{\alpha}\ensuremath{\approx}\ensuremath{-}0.0002$ when ${m}_{\ensuremath{\Phi}}<0.1H$ but increases to positive values as ${m}_{\ensuremath{\Phi}}/H$ increases, with $\ensuremath{\alpha}>0.008$ for ${m}_{\ensuremath{\Phi}}>1.0H$.