Dipole polarizability of 120Sn and nuclear energy density functionals

TL;DR

This study measures the electric dipole polarizability of 120Sn using proton scattering and photoabsorption data, providing insights into nuclear symmetry energy and testing the accuracy of nuclear energy density functionals.

Contribution

It offers the first precise measurement of 120Sn's dipole polarizability and evaluates the performance of various nuclear energy density functionals against experimental data.

Findings

Skyrme-based models describe the data well

Relativistic models generally do not match the data

The measured (120Sn) constrains nuclear symmetry energy

Abstract

The electric dipole strength distribution in 120Sn between 5 and 22 MeV has been determined at RCNP Osaka from a polarization transfer analysis of proton inelastic scattering at E_0 = 295 MeV and forward angles including 0{\deg}. Combined with photoabsorption data an electric dipole polarizability \alpha_D(120Sn) = 8.93(36) fm^3 is extracted. The dipole polarizability as isovector observable par excellence carries direct information on the nuclear symmetry energy and its density dependence. The correlation of the new value with the well established \alpha_D(208Pb) serves as a test of its prediction by nuclear energy density functionals (EDFs). Models based on modern Skyrme interactions describe the data fairly well while most calculations based on relativistic Hamiltonians cannot.