Direct-decay properties of charge-exchange spin giant resonances

Abstract

An extended continuum-RPA approach is applied to describe direct-decay properties of spin giant resonances in $^{208}$Bi and $^{90}$Nb. Partial branching ratios for direct proton decay from these resonances are evaluated. The branching ratio for $\gamma$-decay from the spin-dipole resonance to the Gamow-Teller resonance (main peak) is estimated. The saturation-like behaviour of the mean doorway-state spreading width in $^{208}$Pb is discussed in connection with the branching ratio for direct proton decay from the spin-monopole resonance and the Gamow-Teller strength distribution.Comment: 6 pages, 2 figures, Talk given at the International Conference on Giant Resonances (GR2000),June 2000, Osaka, Japa

Gamow-Teller 1+ states in 112–124Sb isotopes

“…It should be noted that the χ ph and χ pp values were chosen in such a way that the obtained ω GTR values in PM were in good agreement with the corresponding experimental values. According to Rodin et al [49], the calculated ω GTR values in PM are closer to the corresponding experimental data. As can be seen from figure 5, the energy values in PM are smaller than those in SM except for A = 112 isotope.…”

“…This shows that some part of the GTR strength has been transmitted to the pigmy IVSMR region. Furthermore, the GTR states calculated by [49], SM and PM are listed in table 2 in comparison with the corresponding experimental data. The calculated GTR relative strength in PM is found to be in a reasonable agreement with the respective experimental data [55].…”

“…The energies were calculated from the ground state of the parent nucleus. The solid curve with rectangles corresponds to the calculated values by PM, the medium dash line with stars corresponds to the experimental values, the short dash line with circles corresponds to the calculated values by SM and the dotted curve with triangles corresponds to [49]. To investigate the influence of the restoration term (h 0 ) on ω GTR values, the same χ ph and χ pp values were used in the calculations performed by PM and SM.…”

“…The solid curve with rectangules corresponds to the calculated values by PM, the medium dash line with stars corresponds to the experimental values taken from ref. [55], the short dash line with circles corresponds to Rodin et al [49] and the dotted curve with triangles corresponds to the data calculated by the phenomenological formula (ω GTR − ω IAR = 26A −1/3 − 18.5(N − Z)/A MeV) [56]. The ω IAR values in the PM calculations were taken from ref.…”

“…Recently, Babacan et al [48] studied the GT 1 + states in 90 Nb isotopes and it was found that the GT resonance energy was located at 7.61 MeV. Apart from the 90 Zr isotopes, the GT strength distributions in 112−124 Sn isotopes was researched by Rodin and Urin [49] using the partially self-consistent proton neutron quasiparticle continuum random phase approximation (pnQCRPA). In ref.…”