Parity violation in neutron resonances in107,109Ag

Abstract

Parity nonconservation (PNC) was studied in p-wave resonances in Ag by measuring the helicity dependence of the neutron total cross section. Transmission measurements on natural Ag were performed in the energy range 32 to 422 eV with the time-of-flight method at the Manuel Lujan Neutron Scattering Center at Los Alamos National Laboratory. A total of 15 p-wave neutron resonances were studied in ${}^{107}\mathrm{Ag}$ and nine p-wave resonances in ${}^{109}\mathrm{Ag}.$ Statistically significant asymmetries were observed for eight resonances in ${}^{107}\mathrm{Ag}$ and for four resonances in ${}^{109}\mathrm{Ag}.$ An analysis treating the PNC matrix elements as random variables yields a weak spreading width of ${\ensuremath{\Gamma}}_{w}{=(2.67}_{\ensuremath{-}1.21}^{+2.65})\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}7} \mathrm{eV}$ for ${}^{107}\mathrm{Ag}$ and ${\ensuremath{\Gamma}}_{w}{=(1.30}_{\ensuremath{-}0.74}^{+2.49})\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}7} \mathrm{eV}$ for ${}^{109}\mathrm{Ag}.$