Origin of the σAA2/σZZ2 discrepancy between TDRPA and experiment

Investigate the dependence of the ratio of mass-number to charge-number dispersions, σAA2/σZZ2, on the choice of nuclear energy density functional, and ascertain whether including two-body dissipation effects missing from the current time-dependent random phase approximation framework can resolve the discrepancy between theoretical predictions and experimental data.

Background

The paper finds that while TDRPA reproduces mass-number fluctuations, it systematically overestimates charge-number fluctuations, leading to σAA2/σZZ2 values lower than experimental observations. This discrepancy could stem from the specific energy density functional (EDF) used or from dynamical ingredients absent in the current TDRPA formulation, such as two-body dissipation.

The authors explicitly defer targeted investigations of EDF dependence and the impact of two-body dissipation mechanisms to future work, identifying concrete avenues to understand and potentially reconcile theory with experiment.