Problem of parity nonconservation in 57Fe and 119Sn nuclei.

Abstract

We consider parity nonconservation effect for the Mossbauer transitions in $^{57}\mathrm{Fe}$ and $^{119}\mathrm{Sn}$ nuclei. To simplify the calculations we use contact approximation for nucleon-nucleon weak interaction. A corresponding parity nonconserving effective Hamiltonian is presented. The result of the calculation of \ensuremath{\gamma}-quantum circular polarization degree P\ensuremath{\sim}3\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}8}$ strongly contradicts the experimental value P\ensuremath{\sim}${10}^{\mathrm{\ensuremath{-}}3}$. One may consider this huge disagreement as an indication of the unknown nuclear phenomena which leads to the enhancement of parity nonconservation. We stress the importance of a new independent measurement of the effect.