Multi-messenger investigation of the Pygmy Dipole Resonance in 140Ce

D Savran,V Derya,S Bagchi,J Endres,M.N Harakeh,J Isaak,N Kalantar-Nayestanaki,E.G Lanza,B Löher,A Najafi,S Pascu,S.G Pickstone,N Pietralla,V.Yu Ponomarev,C Rigollet,C Romig,M Spieker,A Vitturi,A Zilges

doi:10.1016/j.physletb.2018.09.025

Abstract

We report on the first (p,p′γ) experiments at Ep=80 MeV to investigate the Pygmy Dipole Resonance (PDR) in the semi-magic nucleus 140Ce. This experiment is the latest in a series of experiments to investigate the PDR with different complementary probes to provide a multi-messenger data set on the properties of the PDR in 140Ce. In addition, calculations within the Quasi-particle Phonon Model (QPM) have been performed. Cross sections have been calculated for proton- as well as α-scattering reactions based on the transition densities obtained from the QPM, not only at the RPA level, but including the full model space of up to 3p–3h configurations. This allows for the first time to compare the calculations to the experimental results on an absolute scale for single excitations. Agreement between QPM and experiment is observed, which proves the high accuracy of the calculated transition densities for individual PDR states.

Highlights

We report on the first (p, p γ ) experiments at Ep = 80 MeV to investigate the Pygmy Dipole Resonance (PDR) in the semi-magic nucleus 140Ce
Cross sections have been calculated for proton- as well as α-scattering reactions based on the transition densities obtained from the Quasi-particle Phonon Model (QPM), at the RPA level, but including the full model space of up to 3p–3h configurations
A recent example in the field of astrophysics is the simultaneous observation of gravitational as well as electromagnetic signals from the same astrophysical event, which allowed to identify a binary neutron star merger followed by a γ -ray burst as the common source [1]

Summary

Introduction

Cross sections have been calculated for proton- as well as α-scattering reactions based on the transition densities obtained from the QPM, at the RPA level, but including the full model space of up to 3p–3h configurations. Agreement between QPM and experiment is observed, which proves the high accuracy of the calculated transition densities for individual PDR states.

Results

Conclusion