0000000001234427
AUTHOR
K. Fujita
Complete dipole response in [sup 208]Pb from high-resolution polarized proton scattering at 0°
At the Research Center for Nuclear Physics, Osaka, Japan, the 208Pb(p,p´) reaction was measured at Ep=295 MeV and scattering angles Θlab= 0° - 10°. A high energy resolution of the order of ΔE/E ≈ 8x10^-5 was achieved, corresponding to ΔE=25-30 keV (FWHM). Cross sections were extracted by a multipole decomposition analysis of the angular distributions. Dominant contributions at very forward angles originate from E1 excitation due to Coulomb projectile-target interaction and spin M1 transitions caused by the spin-isospin part of the proton-nucleus interaction. A separation of these contributions was performed with two independent methods, viz. a multipole decomposition of the angular distribu…
Gamow-Teller Transitions and β-decay Half-life in Proton Rich pf-shell Nuclei
In violent neutrino‐induced reactions at the core‐collapse stage of type II supernovae, Gamow‐Teller (GT) transitions starting from stable as well as unstable pf‐shell nuclei play important roles. In the β‐decay study of these unstable pf‐shell nuclei, half‐lives can be measured rather accurately. On the other hand, in high‐resolution (3He,t) charge‐exchange reactions at 0°, individual GT transitions up to high excitations can be studied. Assuming the isospin symmetry for the strengths of Tz = ±2→±1 analogous GT transitions, we present a “merged analysis” for the determination of GT transition strengths starting from proton‐rich Tz = −2 nuclei. We applied this analysis to the A = 52, T = 2 …
Pygmy dipole resonance in Pb-208
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 Jˇ = 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 t…
Gamow-Teller Transitions in Proton Rich Exotic pf-shell Nuclei Deduced from Mirror Transitions
The rp‐process nucleosynthesis proceeds through nuclei near the proton drip‐line, in which Gamow‐Teller (GT) transitions starting from unstable pf‐shell nuclei play important roles. In the β‐decay study of these nuclei, half‐lives can be measured rather accurately. On the other hand, in the high‐resolution (3He, t) charge‐exchange reactions on mirror nuclei, individual GT transitions can be studied up to high excitations. For the accurate study of the GT transition strengths in the A = 52, T = 2, system, we compare and combine the β‐decay study of the proton‐rich nucleus 52Ni and the 52Cr(3He, t) measurement assuming the isospin symmetry of the Tz = ±2→±1 transitions.