Nuclear matrix elements (NMEs) for double beta decays (DBDs) and astro-neutrinos are crucial for neutrino studies by DBDs and astro-neutrino nuclear interactions. The axial-vector NMEs are quenched with respect to the QRPA and other model NMEs due to non-nucleonic effects. The coherent delta (\(\varDelta \))-isobar effect is suggested to reduce the axial-vector NME by a quenching coefficient around 0.6 and 0.95 in medium-heavy and light nuclei, respectively.

中文翻译：

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双 Beta 衰减中的 Delta 等压线效应

双β衰变（DBD）和天体-中微子的核基质元素（NME）对于DBD和天体-中微子核相互作用的中微子研究至关重要。由于非核子效应，轴向矢量 NME 相对于 QRPA 和其他模型 NME 被淬灭。建议相干 delta ( \(\varDelta \) )-isobar 效应在中重核和轻核中分别通过约 0.6 和 0.95 的淬灭系数降低轴向矢量 NME。