<i>P</i>,<i>T</i>-violating nuclear matrix elements in the one-meson exchange approximation

Abstract

Expressions for the P,T-violating NN potentials are derived for \ensuremath{\pi}, \ensuremath{\rho}, and \ensuremath{\omega} exchange. The nuclear matrix elements for \ensuremath{\rho} and \ensuremath{\omega} exchange are shown to be greatly suppressed, so that, under the assumption of comparable coupling constants, \ensuremath{\pi} 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\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}4}$ 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.