Direct proton decay of the isoscalar giant dipole resonance in 208Pb

Nayak, B. K.; Garg, U.; Koss, M.; Li, T.; Martis, E.; Fujimura, H.; Fujiwara, M.; Hara, K.; Kawase, K.; Nakanishi, K.; Obayashi, E.; Yoshida, H. P.; Itoh, M.; Kishi, S.; Sakaguchi, H.; Uchida, M.; Yasuda, Y.; Yosoi, M.; Zegers, R. G. T.; Akimune, H.; Harakeh, M. N.; Hunyadi, M.

Direct proton decay of the isoscalar giant dipole resonance in 208Pb

Authors

Description

The excitation and subsequent proton decay of the isoscalar giant dipole resonance (ISGDR) in $^{208}$Pb have been investigated via the $^{208}$Pb($α, α^{\prime}p)^{207}$Tl reaction at 400 MeV. Excitation of the ISGDR has been identified by the difference-of-spectra method. The enhancement of the ISGDR strength at high excitation energies observed in the multipole-decomposition-analysis of the singles $^{208}$Pb($α,α^{\prime}$) spectra is not present in the excitation energy spectrum obtained in coincidence measurement. The partial branching ratios for direct proton decay of ISGDR to low-lying states of $^{207}$Tl have been determined and the results are compared with predictions of continuum random-phase-approximation (CRPA) calculations.
12 pages, 4 figures; accepted for publication in Physics Letters B