P,T-violating nuclear matrix elements in the one-meson exchange approximation.

Abstract

Expressions for the [ital P],[ital T]-violating [ital NN] potentials are derived for [pi], [rho], and [omega] exchange. The nuclear matrix elements for [rho] and [omega] exchange are shown to be greatly suppressed, so that, under the assumption of comparable coupling constants, [pi] exchange would dominate by two orders of magnitude. The ratio of [ital P],[ital T]-violating to [ital P]-violating matrix elements is found to remain approximately constant across the nuclear mass table, thus establishing the proportionality between time-reversal-violation and parity-violation matrix elements. The calculated values of this ratio suggest a need to obtain an accuracy of order 5[times]10[sup [minus]4] for the ratio of the [ital PT]-violating to [ital P]-violating asymmetries in neutron transmission experiments in order to improve on the present limits on the isovector pion coupling constant.