Accessing the Single-Particle Structure of the Pygmy Dipole Resonance in $^{208}$Pb

TL;DR

This paper presents new experimental data on the neutron single-particle nature of the Pygmy Dipole Resonance in $^{208}$Pb, using $(d,p)$ and proton scattering experiments, and compares findings with theoretical models to understand its microscopic structure.

Contribution

It introduces $(d,p)$ reactions as a new experimental method to probe the PDR's single-particle characteristics in $^{208}$Pb and compares results with advanced theoretical models.

Findings

$(d,p)$ reactions effectively probe PDR single-particle states.

Experimental data align with shell-model and energy-density functional predictions.

The study enhances understanding of PDR collectivity and microscopic structure.

Abstract

New experimental data on the neutron single-particle character of the Pygmy Dipole Resonance (PDR) in $^{208}$Pb are presented. They were obtained from $(d,p)$ and resonant proton scattering experiments performed at the Q3D spectrograph of the Maier-Leibnitz Laboratory in Garching, Germany. The new data are compared to the large suite of complementary, experimental data available for $^{208}$Pb and establish $(d,p)$ as an additional, valuable, experimental probe to study the PDR and its collectivity. Besides the single-particle character of the states, different features of the strength distributions are discussed and compared to Large-Scale-Shell-Model (LSSM) and energy-density functional (EDF) plus Quasiparticle-Phonon Model (QPM) theoretical approaches to elucidate the microscopic structure of the PDR in $^{208}$Pb.