Affleck-Dine sneutrino inflation

Motivated by the coincidence between the Hubble scale during inflation and the typical seesaw neutrino mass scale, we present a supergravity model in which the inflaton is identified with a linear combination of right-handed sneutrino fields. The model accommodates an inflaton potential that is flatter than quadratic chaotic inflation, resulting in a tensor-to-scalar ratio that is measurable but not yet ruled out. Small $CP$ violation in the neutrino mass matrix and supersymmetry breaking yield an evolution in the complex plane for the sneutrino fields. This induces a net lepton charge that, via the Affleck–Dine mechanism, can be the origin of the observed baryon asymmetry of the Universe.

Figure 1

Values of the spectral tilt $n_s$ and the tensor-to-scalar ratio $r$ for $N=50$ (red solid lines) and $N=60$ (green dotted line). Each line is obtained by varying ${\mu }_R$. From top to bottom, the points on the lines correspond to the values ${\mu }_R=(0,1,2,3,4)\times {10}^{-2}$, respectively. The Planck contours are obtained from Fig. 21 of Ref. [22]. The top points ${\mu }_R=0$ correspond to quadratic chaotic inflation. As discussed in the main text, in the $N=60$ case, isocurvature perturbations can be disregarded for ${\mu }_R\gtrsim 0.025$.