| Title: |
Fine Structure of the Isovector Giant Dipole Resonance in $^{142-150}$Nd and $^{152}$Sm |
| Authors: |
Donaldson, L. M., Carter, J., von Neumann-Cosel, P., Nesterenko, V. O., Neveling, R., Reinhard, P. -G., Usman, I. T., Adsley, P., Bertulani, C. A., Brümmer, J. W., Buthelezi, E. Z., Cooper, G. R. J., Fearick, R. W., Förtsch, S. V., Fujita, H., Fujita, Y., Jingo, M., Kheswa, N. Y., Kleinig, W., Kureba, C. O., Kvasil, J., Latif, M., Li, K. C. W., Mira, J. P., Nemulodi, F., Papka, P., Pellegri, L., Pietralla, N., Ponomarev, V. Yu., Rebeiro, B., Richter, A., Shirikova, N. Yu., Sideras-Haddad, E., Sushkov, A. V., Smit, F. D., Steyn, G. F., Swartz, J. A., Tamii, A. |
| Source: |
Phys. Rev. C 102, 064327 (2020) |
| Publication Year: |
2020 |
| Collection: |
Nuclear Experiment |
| Subject Terms: |
Nuclear Experiment |
| More Details: |
Background: Inelastic proton scattering at energies of a few hundred MeV and very-forward angles including $0^\circ$ has been established as a tool to study electric-dipole strength distributions in nuclei. The present work reports a systematic investigation of the chain of stable even-mass Nd isotopes representing a transition from spherical to quadrupole-deformed nuclei. Purpose: Extraction of the equivalent photo-absorption cross sections and analysis of their fine structure in the energy region of the IsoVector Giant Dipole Resonance (IVGDR). Method: Proton inelastic scattering reactions of 200 MeV protons were measured at iThemba LABS in Cape Town, South Africa. The scattering products were momentum-analysed by the K600 magnetic spectrometer positioned at $\theta_{\mathrm{Lab}}=0^\circ$. Using dispersion-matching techniques, energy resolutions of $\Delta E \approx 40 - 50$ keV were obtained. After subtraction of background and contributions from other multipoles, the spectra were converted to photo-absorption cross sections using the equivalent virtual-photon method. Results: Wavelet-analysis techniques are used to extract characteristic energy scales of the fine structure of the IVGDR from the experimental data. Comparisons with the Quasiparticle-Phonon Model (QPM) and Skyrme Separable Random Phase Approximation (SSRPA) predictions provide insight into the role of different giant resonance damping mechanisms. Conclusions: Fine structure is observed even for the most deformed nuclei studied. Fragmentation of the one particle-one hole ($1p1h$) strength seems to be the main source of fine structure in both spherical and deformed nuclei. Some impact of the spreading due to coupling of the two particle-two hole ($2p2h$) states to the $1p1h$ doorway states is seen in the spherical/transitional nuclei, where calculations beyond the $1p1h$ level are available.
Comment: 17 pages, 17 figures; Minor changes made such as those clarifying the descriptions of the analysis procedure, but the results are unchanged. The current version was accepted for publication by PRC on 7 December 2020 |
| Document Type: |
Working Paper |
| DOI: |
10.1103/PhysRevC.102.064327 |
| Access URL: |
http://arxiv.org/abs/2010.01210 |
| Accession Number: |
edsarx.2010.01210 |
| Database: |
arXiv |
