In a recent experiment, carried out at RIBF/RIKEN, the ${}^{25}$F$(p,2p)$${}^{24}$O reaction was studied at 270 MeV/A in inverse kinematics. Derived spectroscopic factors suggest that the effective core of ${}^{25}$F significantly differs from a free ${}^{24}$O nucleus. We interpret these results within the Particle-Rotor Model and show that the experimental level scheme of ${}^{25}$F can be understood in the rotation-aligned coupling scheme, with its $5/2_1^{+}$ ground state as the band-head of a decoupled band. The excitation energies of the observed $1/2_1^{+}$ and $9/2_1^{+}$ states correlate strongly with the rotational energy of the effective core, seen by the odd proton, and allow us to estimate its $2^{+}$ energy at $\approx$ 3.2 MeV and a moderate quadrupole deformation, ${ϵ}_2\approx 0.15$. The measured fragmentation of the $\pi d_{5/2}$ single-particle strength is discussed and some further experiments suggested.

中文翻译：

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旋转模型中25F的核心

在RIBF / RIKEN进行的一项最新实验中， ${}^{25}$F$（p，2p）$${}^{24}$在反向运动学中以270 MeV / A研究了O反应。派生的光谱因素表明，有效的核心${}^{25}$F明显不同于自由 ${}^{24}$O核。我们在“粒子转子模型”中解释了这些结果，并证明了${}^{25}$F在旋转对齐耦合方案中可以理解为 $5/2_{\mathrm{1个}}^{+}$基态作为去耦频带的带头。所观察到的激发能$\mathrm{1个}/2_{\mathrm{1个}}^{+}$ 和 $9/2_{\mathrm{1个}}^{+}$ 状态与奇质子看到的有效核的旋转能密切相关，并允许我们估计其 $2^{+}$ 能量在 $\approx$ 3.2 MeV和适度的四极变形， ${ϵ}_2\approx 0.15$。测得的碎片$\pi d_{5/2}$ 讨论了单颗粒强度，并提出了一些进一步的实验。