Kinematically Blocked Curvaton
  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 $f_{NL}=100$. 
Lu-Yun Lee, Chia-Min Lin and Chian-Shu Chen
astro-ph.CO hep-ph