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arXiv 0705.1753nucl-ex
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富中子核$^{26}$ Ne中低偶极强度的寻找

Search for low lying dipole strength in the neutron rich nucleus $^{26}$Ne

J. Gibelin, D. Beaumel, T. Motobayashi, N. Aoi, H. Baba, Y. Blumenfeld, Z. Elekes, S. Fortier, N. Frascaria, N. Fukuda, T. Gomi, K. Ishikawa, Y. Kondo, T. Kubo,… 展开作者

J. Gibelin, D. Beaumel, T. Motobayashi, N. Aoi, H. Baba, Y. Blumenfeld, Z. Elekes, S. Fortier, N. Frascaria, N. Fukuda, T. Gomi, K. Ishikawa, Y. Kondo, T. Kubo, V. Lima, T. Nakamura, A. Saito, Y. Satou, E. Takeshita, S. Takeuchi, T. Teranishi, Y. Togano, A. M. Vinodkumar, Y. Yanagisawa, K. Yoshida

摘要:

在58 A.MeV下测量了外来丰中子核$^{26}$ Ne在$^{nat}$ Pb靶上的库仑激发,以寻找高于中子发射阈值的低E1强度。还对$^{nat}$ Al靶进行了数据采集,以估计核贡献。放射性核束是由理化学研究所提供的95 A.MeV $^{40}$ Ar束分裂产生的。该装置包括一个碘化钠伽马射线阵列,一个带电碎片hodoscope和中子墙。在$^{25}$ Ne+n通道中使用不变质量方法,我们观察到相当数量的E1强度在6和10 MeV之间。重建的$^{26}$ Ne角分布证实了它的E1性质。导出了约化偶极跃迁几率B(E1)=0.49 $\pm$ 0.16 $e^2fm^2$.首次得到了丰中子核低激发强度的衰变图。结果进行了讨论,在一个pygmy共振中心约9兆电子伏。

英文摘要:

Coulomb excitation of the exotic neutron-rich nucleus $^{26}$Ne on a $^{nat}$Pb target was measured at 58 A.MeV in order to search for low-lying E1 strength above the neutron emission threshold. Data were also taken on an $^{nat}$Al target to estimate the nuclear contribution. The radioactive beam was produced by fragmentation of a 95 A.MeV $^{40}$Ar beam delivered by the RIKEN Research Facility. The set-up included a NaI gamma-ray array, a charged fragment hodoscope and a neutron wall. Using the invariant mass method in the $^{25}$Ne+n channel, we observe a sizable amount of E1 strength between 6 and 10 MeV. The reconstructed $^{26}$Ne angular distribution confirms its E1 nature. A reduced dipole transition probability of B(E1)=0.49$\pm$0.16 $e^2fm^2$ is deduced. For the first time, the decay pattern of low-lying strength in a neutron-rich nucleus is obtained. The results are discussed in terms of a pygmy resonance centered around 9 MeV.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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