Structure of low-energy collective 0−-states in doubly magic nuclei and matrix elements of the P-odd and P- and T-odd weak interaction

The structure of the collective low-energy Jπ = 0− (T = 0 and T = 1) modes is studied for a doubly magic nucleus in a simplified analytic model of RPA. The 0− phonon states (T = 0, 1) lie at energies ET=0(0−) ≲ ω and ET=1(0−) > ω, where ω is the oscillator frequency. The matrix elements of P-odd and P- and T-odd weak one-body potentials connecting the ground state to these 0−-states, Wcoll, are enhanced by the factor ∼ 2(ωE)12A13 ∼ 10 as compared to the single-particle value wsp what can result in values |Wcoll| ∼ 20–30 eV if standard values of DDH parameters are used for wsp. Similar enhancement arises in the P- and T-odd case.