Resonant particle production with non-minimally coupled scalar fields in preheating after inflation

Abstract

We investigate a resonant particle production of a scalar field $\chi$ coupled non-minimally to a spacetime curvature $R$ ($\xi R{\chi }^2$) as well as to an inflaton field $\varphi$ ($g^2{\varphi }^2{\chi }^2$). In the case of $g<3\times 10^{-4}$, $\xi$ effect assists $g$-resonance in certain parameter regimes. However, for $g>3\times 10^{-4}$, $g$-resonance is not enhanced by $\xi$ effect because of $\xi$ suppression effect as well as a back reaction effect. If $\xi \approx -4$, the maximal fluctuation of produced $\chi$-particle is ${\sqrt{<{\chi }^2>}}_{max}\approx 2\times 10^{17}$ GeV for $g<1\times 10^{-5}$, which is larger than the minimally coupled case with $g\approx 1\times 10^{-3}$.

Comments: 33pages, 12figures. to appear in Physical Review D