Title: Implications of a Weakening N = 126 Shell Closure Away from Stability for r-Process Astrophysical Conditions Show Chinese title

Title: 稳定性以外的N = 126壳层减弱对r过程天体物理条件的影响

Abstract: The formation of the third r-process abundance peak near A = 195 is highly sensitive to both nuclear structure far from stability and the astrophysical conditions that produce the heaviest elements. In particular, the N = 126 shell closure plays a crucial role in shaping this peak. Experimental data hints that the shell weakens as proton number departs from Z = 82, a trend largely missed by global mass models. To investigate its impact on r-process nucleosynthesis, we employ both standard global models with strong closures and modified Duflo-Zuker (DZ) models that reproduce the weakening, combined with three sets of beta minus decay rates. Strong shell closures generate sharply peaked abundances, whereas weakened closures consistent with the experimental trend produce broader, flatter patterns. Accurately reproducing the solar third peak under weakened shell strength requires highly neutron-rich conditions (Ye <= 0.175) and slower decay rates. These results demonstrate that a weakening N = 126 shell closure away from stability imposes significant constraints on the astrophysical environments of the r-process and underscores the need for precise mass measurements and improved characterization of beta minus decay properties in this region. Show Chinese abstract

Abstract: 第三r过程丰度峰在A = 195附近的形成对远离稳定线的核结构以及产生最重元素的天体物理条件非常敏感。 特别是，N = 126壳层闭合在此峰的形成中起着关键作用。 实验数据表明，当质子数偏离Z = 82时，该壳层会变弱，这一趋势在全局质量模型中大多被忽略了。 为了研究其对r过程核合成的影响，我们采用了具有强闭合性的标准全局模型以及能够再现这种变弱现象的修改后的Duflo-Zuker（DZ）模型，并结合了三组β减衰率。 强壳层闭合会产生尖锐的丰度峰，而与实验趋势一致的弱化闭合则会产生更宽、更平的模式。 在弱化壳层强度下准确再现太阳的第三峰需要高度中子丰富的条件（Ye <= 0.175）和较慢的衰变率。 这些结果表明，远离稳定线的N = 126壳层闭合的减弱对r过程的天体物理环境施加了重要的限制，并强调了在此区域进行精确的质量测量和改进β减衰性质表征的必要性。