Pygmy dipole resonance in 208Pb
Abstract
Scattering of protons of several hundred MeV is a promising new spectroscopic tool for the study of electric dipole strength in nuclei. A case study of 208Pb shows that at very forward angles J^pi = 1- states are strongly populated via Coulomb excitation. A separation from nuclear excitation of other modes is achieved by a multipole decomposition analysis of the experimental cross sections based on theoretical angular distributions calculated within the quasiparticle-phonon model. The B(E1) transition strength distribution is extracted for excitation energies up to 9 MeV, i.e., in the region of the so-called pygmy dipole resonance (PDR). The Coulomb-nuclear interference shows sensitivity to the underlying structure of the E1 transitions, which allows for the first time an experimental extraction of the electromagnetic transition strength and the energy centroid of the PDR.
Cite
@article{arxiv.1203.2155,
title = {Pygmy dipole resonance in 208Pb},
author = {I. Poltoratska and P. von Neumann-Cosel and A. Tamii and T. Adachi and C. A. Bertulani and J. Carter and M. Dozono and H. Fujita and K. Fujita and Y. Fujita and K. Hatanaka and M. Itoh and T. Kawabata and Y. Kalmykov and A. M. Krumbholz and E. Litvinova and H. Matsubara and K. Nakanishi and R. Neveling and H. Okamura and H. J. Ong and B. Özel-Tashenov and V. Yu. Ponomarev and A. Richter and B. Rubio and H. Sakaguchi and Y. Sakemi and Y. Sasamoto and Y. Shimbara and Y. Shimizu and F. D. Smit and T. Suzuki and Y. Tameshige and J. Wambach and M. Yosoi and J. Zenihiro},
journal= {arXiv preprint arXiv:1203.2155},
year = {2015}
}
Comments
submitted to Phys. Rev. C