Leptogenesis in inflationary models with non-Abelian gauge fields.

A scenario of leptogenesis was introduced in Alexander et al. (Phys Rev Lett 96:081301, <xref>2006</xref>) which works during inflationary period within standard model of particle physics setup. In this scenario lepton number is created by the gravitational chiral anomaly which has a non-zero expectation value for models of inflation driven by pseudoscalar field(s). Here, we observe that models of inflation involving non-Abelian gauge fields, e.g. the chromo-natural inflation (Adshead and Wyman in Phys Rev Lett 108:261302, <xref>2012</xref>) or the gauge-flation (Maleknejad and Sheikh-Jabbari in Phys Lett B 723:224, <xref>2013</xref>. <ext-link>arXiv:1102.1513</ext-link> [hep-ph]), have a parity-violating tensor mode (graviton) spectrum and naturally lead to a non-vanishing expectation value for the gravitational chiral anomaly. Therefore, one has a natural leptogenesis scenario associated with these inflationary setups, inflato-natural leptogenesis. We argue that the observed value of baryon-to-photon number density can be explained in a natural range of parameters in these models. [ABSTRACT FROM AUTHOR]