Enhancement of parity violating mixing in halo nuclei and the problem of neutron weak parity nonconserving potential constant

We consider the parity nonconserving (PNC) mixing in the ground state of exotic (halo) nuclei caused by the PNC weak interaction between outer neutron and nucleons within the nuclear interior. For the nucleus ¹¹Be as an example of a typical nucleus with a neutron halo, we use an analytical model for the external neutron wave functions to estimate the scale of the PNC mixing. The amplitude of the PNC mixing in the halo state is found to be an order of magnitude bigger than that of typical PNC mixing between the “normal” nuclear states in nearby nuclei. The enhanced PNC mixing in a halo cloud is proportional to the neutron weak PNC potential constant g_n^W only.