P,T-Violating Nuclear Matrix Elements in the One-Meson Exchange Approximation

Abstract

Expressions for the P,T-violating NN potentials are derived for $π$, $ρ$ and $ω$ exchange. The nuclear matrix elements for $ρ$ and $ω$ exchange are shown to be greatly suppressed, so that, under the assumption of comparable coupling constants, $π$ exchange would dominate by two orders of magnitude. The ratio of P,T-violating to 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^{-4}$ for the ratio of the PT-violating to P-violating asymmetries in neutron transmission experiments in order to improve on the present limits on the isovector pion coupling constant.