Our understanding of the low-lying resonance structure in \(^{12}\)C remains incomplete. We have used the \(^{11}\text {B}(p,3\alpha )\gamma \) reaction at proton energies of \(E_p=0.5\)–2.7 MeV as a selective probe of the excitation region above the \(3\alpha \) threshold in \(^{12}\)C. Transitions to individual levels in \(^{12}\)C were identified by measuring the 3\(\alpha \) final state with a compact array of charged-particle detectors. Previously identified transitions to narrow levels were confirmed and new transitions to broader levels were observed for the first time. Here, we report cross sections, deduce partial \(\gamma \)-decay widths and discuss the relative importance of direct and resonant capture mechanisms.

中文翻译：

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$$$ {{11} \ text {B}（p，3 \ alpha）\ gamma $$ 11 B（p，3α）γ反应的实验研究，$$ E_p = 0.5 $$ E p = 0.5 –2.7病毒

我们对\（^ {12} \） C中低层共振结构的理解仍然不完整。我们使用质子能为（E_p = 0.5 \）– 2.7 MeV的\（^ {11} \ text {B}（p，3 \ alpha）\ gamma \）反应作为上述激发区的选择性探针\（^ {12} \） C中的\（3 \ alpha \）阈值。通过测量3 \（\ alpha \）最终状态来确定\（^ {12} \） C中各个级别的转换。紧凑的带电粒子检测器阵列。确认了先前确定的向较窄水平的过渡，并且首次观察到向较宽水平的新过渡。在这里，我们报告横截面，推导部分\（\ gamma \）衰减宽度并讨论直接和共振捕获机制的相对重要性。