The neutrino energy loss by electron capture of nuclides 55Co and 56Ni in explosive stellar environments

Abstract

Using the Shell-Model Monte Carlo method and the Random Phase Approximation theory, we carry out an estimation of neutrino energy loss (NEL) for 55Co and 56Ni by electron capture. We find that the NEL rates increase greatly at some typical stellar conditions, and can even exceed five orders of magnitude (e.g. T9 = 38.5, Ye = 0.42 for 56Ni). On the other hand, the error factor C shows that the fit is fairly good for two results at higher density and lower temperature, and the maximum error is ∼ 1.2%. However, the maximum error is ∼ 55.60% (e.g. T9 = 18.5, Ye = 0.45) at lower density and higher temperature.