New inflation, preinflation, and leptogenesis

Abstract

We present a new inflation model in which the inflationary scenario including subsequent reheating is determined in part by a U(1)_R\times Z_n symmetry. A preinflation epoch can be introduced to yield, among other things, a running spectral index indicated by the WMAP analysis. The inflaton decay into right handed neutrinos, whose masses can be hierarchical because of the Z_n symmetry, leads to a reheat temperature >~10^8 GeV (~10^4-10^6 GeV in some cases), followed by non-thermal leptogenesis.

14 pages, 4 figures, revtex4. v2: no changes in content, page layout corrected. v3: the erroneous mention of new inflation as inverted hybrid inflation is corrected. v4: slightly abridged, matches published version