Phonon-particle coupling effects in odd-even mass differences of semi-magic nuclei

TL;DR

This paper introduces a method to incorporate particle-phonon coupling effects into the calculation of odd-even mass differences in semi-magic nuclei, improving the accuracy of theoretical predictions compared to experimental data.

Contribution

It presents a novel approach using Dyson equation solutions with PC corrections to enhance mass difference calculations in semi-magic nuclei.

Findings

PC corrections reduce deviation from experimental data to 0.218 MeV.

Fayans EDF DF3-a provides high baseline accuracy for mass differences.

Including phonon effects improves theoretical predictions significantly.

Abstract

A method to evaluate the particle-phonon coupling (PC) corrections to the single-particle energies in semi-magic nuclei, based on a direct solving the Dyson equation with PC corrected mass operator, is used for finding the odd-even mass difference between 18 even Pb isotopes and their odd-proton neighbors. The Fayans energy density functional (EDF) DF3-a is used which gives rather high accuracy of the predictions for these mass differences already on the mean-field level, with the average deviation from the existing experimental data equal to 0.389 MeV. It is only a bit worse than the corresponding value of 0.333 MeV for the Skyrme EDF HFB-17 which belongs to a family of Skyrme EDFs with the highest overall accuracy in describing the nuclear masses. Account for the PC corrections induced by the low-laying phonons $2^+_1$ and $3^-_1$ significantly diminishes the deviation of the theory from the data till 0.218 MeV.