在最近的SHIP实验中，获得了超过20种从铅到钍区域中最中子亏损核素的$alpha$衰变的详细数据。首次清晰表明，穿越$Z=82$壳层到更高的质子数显著加速了$alpha$衰变。通过实验数据和通用衰变定律，探讨了$alpha$粒子形成概率，并在配对力作用的框架下讨论了这些概率。实验结果与从实验结合能推导出的配对间隙显示出惊人的相似性，进一步证实了$N=126$和$Z=82$壳闭合对$alpha$形成概率的强烈影响。
摘要：
In recent experiments at the velocity filter Separator for Heavy Ion reaction Products (SHIP) (GSI, Darmstadt), an extended and improved set of $ensuremath{alpha}$-decay data for more than 20 of the most neutron-deficient isotopes in the region from lead to thorium was obtained. The combined analysis of this newly available $ensuremath{alpha}$-decay data, of which the $^{186}mathrm{Po}$ decay is reported here, allowed us for the first time to clearly show that crossing the $Z=82$ shell to higher proton numbers strongly accelerates the $ensuremath{alpha}$ decay. From the experimental data, the $ensuremath{alpha}$-particle formation probabilities are deduced following the Universal Decay Law approach. The formation probabilities are discussed in the framework of the pairing force acting among the protons and the neutrons forming the $ensuremath{alpha}$ particle. A striking resemblance between the phenomenological pairing gap deduced from experimental binding energies and the formation probabilities is noted. These findings support the conjecture that both the $N=126$ and $Z=82$ shell closures strongly influence the $ensuremath{alpha}$-formation probability.
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