Resonant particle production with nonminimally coupled scalar fields in preheating after inflation

We investigate the resonant particle production of a scalar field chi coupled nonminimally to a spacetime curvature R (xi R chi(2)) as well as to an inflaton field phi (g(2)phi(2)chi(2)) In the case of g less than or similar to 3 x 10(-4), the xi effect assists g resonance in certain parameter regimes. However, for g greater than or similar to 3 x 10(-4), g resonance is not enhanced by the xi effect because of the xi suppression effect as well as a back reaction effect. If xi approximate to -4, the maximal fluctuation of produced chi particles is root[chi(2)](max) approximate to 2 x 10(17) GeV for g less than or similar to 1 x 10(-5), which is larger than the minimally coupled case with g approximate to 1 x 10(-3). [S0556-2821(99)00618-9].