AI 中文总结
本研究通过采用更精确的质量过剩值重新计算$^{45}$V($p,γ$)$^{46}$Cr反应率，发现该修正率可提升20倍太阳质量模型中$^{44}$Ti产额约26%，且其对$^{44}$Ti生成的影响取决于喷流电子丰度。
AI 中文摘要
热核反应$^{45}$V($p,γ$)$^{46}$Cr是核心坍缩超新星（CCSN）富α冻结阶段中$^{44}$Ti-$^{45}$V准平衡集群的主要泄漏途径，决定了γ射线发射同位素$^{44}$Ti的最终丰度。近期一项高分辨率γ射线研究[C. Cousins等人，《物理评论快报》第136卷，252701页（2026年）]在$^{46}$Cr中发现了10个此前未知的低自旋质子未束缚态，结合AME2020质量过剩值ME($^{46}$Cr)=-29472(11)keV，首次实现了实验约束的$^{45}$V($p,γ$)$^{46}$Cr反应率。本文采用精度提升4倍的CSRe质量过剩值ME($^{46}$Cr)=-29477.2(2.6)keV[M. Wang等人，《物理评论C》第106卷，L051301页（2022年）]重新计算反应率，纳入$^{45}$V基态及前两个激发态的质子俘获过程，结合新的壳模型质子光谱因子，将质量相关的反应率不确定性降至次要水平。修正后的反应率在富α冻结温度（$T\backsimeq1.5$--2 GK）下比Cousins等人的结果最高高出69%。CCSN核合成计算显示，与The等人[《天体物理学杂志》第504卷，500页（1998年）]的结果相比，该修正率使20$M_\bigodot$模型中喷出的$^{44}$Ti产额增加约26%，但对SN 1987A轨迹的影响可忽略不计。研究证实，$^{44}$Ti生成的敏感性由喷流电子丰度（$Y_e$）决定：该反应对富质子喷流（$Y_e\backsimeq0.50$）影响显著，但对富中子喷流（$Y_e\backsimeq0.496$）几乎无影响，后者因自由质子丰度较低抑制了反应流，这调和了过往敏感性研究的矛盾结果。
英文摘要
The thermonuclear $^{45}$V($p,γ$)$^{46}$Cr reaction is the primary leakage pathway from the $^{44}$Ti--$^{45}$V quasi-equilibrium cluster during $α$-rich freeze-out in core-collapse supernovae (CCSN), governing the final abundance of the $γ$-ray-emitting isotope $^{44}$Ti. A recent high-resolution $γ$-ray study [C. Cousins \textit{et al.}, Phys. Rev. Lett. 136, 252701 (2026)] identified ten previously unknown low-spin proton-unbound states in $^{46}$Cr, enabling the first experimentally constrained $^{45}$V($p,γ$)$^{46}$Cr reaction rate using the AME2020 mass excess, $\text{ME}(^{46}\text{Cr}) = -29472(11)$~keV. Here, we adopt the four-fold more precise CSRe mass excess $\text{ME}(^{46}\text{Cr}) = -29477.2(2.6)$~keV [M.~Wang \textit{et al.}, Phys. Rev. C \textbf{106}, L051301 (2022)] to recalculate the reaction rate. Including proton capture on the ground and first two excited states of $^{45}$V alongside new shell-model proton spectroscopic factors, we reduce mass-related rate uncertainties to a subdominant level. The revised rate is up to 69% higher than that of Cousins \textit{et al.} at $α$-rich freeze-out temperatures ($T \simeq 1.5$--$2$~GK). CCSN nucleosynthesis calculations show this revised rate increases the ejected $^{44}$Ti yield by $\sim$26% in a $20\,M_\odot$ model compared to The \textit{et al.} [ApJ \textbf{504}, 500 (1998)], while causing negligible changes for the SN~1987A trajectory. We demonstrate that $^{44}$Ti production sensitivity is dictated by the ejecta electron fraction ($Y_e$): the reaction significantly affects proton-rich ejecta ($Y_e \approx 0.50$) but has little impact on neutron-rich ejecta ($Y_e \approx 0.496$), where lower free-proton abundances suppress reaction flow. This reconciles conflicting results from past sensitivity studies.
