Coupled-channel treatment of $${\varvec{^7}}$$Li$${\varvec{(n,\gamma )^8}}$$Li in effective field theory
Coupled-channel treatment of $${\varvec{^7}}$$Li$${\varvec{(n,\gamma )^8}}$$Li in effective field theory
复制标题
有效场论中 $${varvec{^7}}$$Li$${varvec{(n,gamma )^8}}$$Li 的耦合通道处理
DOI：
10.1140/epja/s10050-021-00516-6
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发表时间：
2021
期刊：
影响因子：
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通讯作者：
Rupak, Gautam
中科院分区：
文献类型：
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作者：
Higa, Renato;Premarathna, Pradeepa;Rupak, Gautam
计算了低能下E1对俘获反应的贡献。我们采用耦合通道的形式主义，占激发核心的贡献。我们发展了一个晕有效场理论功率计数，其中自旋通道中的捕获比通道中的捕获增强。一个下一个领先的顺序计算的激发核心的贡献示出只影响整体归一化的横截面。因此，俘获截面的动量依赖性在有或没有激发自由度的理论中是相同的。在动量低于1 MeV时，核心的运动学特征可以忽略不计，只有在共振能量之外才有意义，尽管仍然与次-领先阶修正相容。我们将我们的形式主义与以前的晕有效场论计算[Zhang et al.，Phys.Rev.C89，024613（2014）]，其也将核心视为明确的自由度。我们的形式化表述和分析在几个方面与这一早期工作不一致。
The E1 contribution to the capture reactionis calculated at low energies. We employ a coupled-channel formalism to account for theexcited core contribution. We develop a halo effective field theory power counting where capture in the spinchannel is enhanced over thechannel. A next-to-leading order calculation is presented where the excited core contribution is shown to affect only the overall normalization of the cross section. The momentum dependence of the capture cross section, as a consequence, is the same in a theory with or without the exciteddegree of freedom at this order of the calculation. The kinematical signature of thecore is negligible at momenta below 1 MeV and significant only beyond theresonance energy, though still compatible with a next-to-next-to-leading order correction. We compare our formalism with a previous halo effective field theory calculation [Zhang et al., Phys. Rev. C89, 024613 (2014)] that also treated thecore as an explicit degree of freedom. Our formal expressions and analysis disagree with this earlier work in several aspects.