Kinematically Blocked Curvaton

TL;DR

This paper explores a curvaton decay mechanism that is kinematically blocked, allowing for larger coupling constants and providing bounds on the Hubble parameter, with implications for non-Gaussianity in the early universe.

Contribution

It introduces the concept of kinematically blocked curvaton decay, expanding the parameter space and constraints of curvaton models in cosmology.

Findings

Coupling constant for decay can be as large as order 1.

Lower bound on Hubble parameter at horizon exit is approximately 10^{10} GeV.

Nonlinear parameter f_NL can reach values up to 100.

Abstract

In this paper, we investigate the idea that the decay of a curvaton is kinematically blocked and show that the coupling constant for curvaton decay can be as large as ${\cal O}(1)$. We also find in this case the lower bound of the Hubble parameter at horizon exit from big bang nucleosynthesis (BBN) is $H_\ast \gae 7.2 \times 10^{-9}M_P \sim 10^{10} {GeV}$. Similar to conventional curvaton scenario, the nonlinear parameter can be as large as $f_{NL}=100$.