Abstract
The nature of J = 1− levels of 96Zr below the -decay Q value of 96Y has been investigated in high-resolution -ray spectroscopy following the decay as well as in a campaign of inelastic photon scattering experiments. Branching ratios extracted from decay allow the absolute E1 excitation strength to be determined for levels populated in both reactions. The combined data represents a comprehensive approach to the wavefunction of 1− levels below the Q value, which are investigated in the theoretical approach of the Quasiparticle Phonon Model. This study clarifies the nuclear structure properties associated with the enhanced population of high-lying levels in the 96Ygs decay, one of the three most important contributors to the high-energy reactor antineutrino spectrum.