论文标题
使用TPC的Hoyle状态直接 - 末期组件几乎无中等的测量
Almost medium-free measurement of the Hoyle state direct-decay component with a TPC
论文作者
论文摘要
背景:Hoyle State的结构是$^{12} \ Mathrm {C} $的高度$α$ clustered状态,长期以来一直是辩论的主题。通过研究Hoyle状态的衰减分支,可以了解该系统是否包括0s轨道中的三个弱相互互动的$α$粒子,称为$α$ - 固定状态。目的:可以通过研究由衰减引起的3 $α$台球的能量分区来识别Hoyle状态的直接衰减,而不是通过$^{8} \ Mathrm {Be} $ the状态来直接衰减。本文提供了有关使用新的实验技术说明Hoyle的分手机制的详细信息。方法:通过使用Texat(Texas Active Target)TPC使用$^{12} \ Mathrm {n} $的β剥离带电粒子光谱,可以在无需贡献堆积事件的情况下对直接3 $α$衰减比率进行高敏性测量。结果:一种通过似然函数理解直接组件的贡献的贝叶斯方法表明,在95 \%置信度下,直接组件为$ <0.043 \%$(C.L.)。该值与其他几项研究一致,在这里我们可以证明,衰减分数约为$ 10^{ - 4} $的小型非顺序组件很可能是很可能的。结论:首次以几乎无中等反应进行Hoyle状态衰减的非顺序分量的测量。派生的上限与以前的研究一致,并证明了对绝对分支比率的敏感性。需要将进一步的实验研究与对衰减动力学的强大显微理论理解相结合,以提供对Hoyle状态作为$α$ condemensate的想法的更多见解。
Background: The structure of the Hoyle state, a highly $α$-clustered state at 7.65 MeV in $^{12}\mathrm{C}$, has long been the subject of debate. Understanding if the system comprises of three weakly-interacting $α$-particles in the 0s orbital, known as an $α$-condensate state, is possible by studying the decay branches of the Hoyle state. Purpose: The direct decay of the Hoyle state into three $α$-particles, rather than through the $^{8}\mathrm{Be}$ ground state, can be identified by studying the energy partition of the 3 $α$-particles arising from the decay. This paper provides details on the break-up mechanism of the Hoyle stating using a new experimental technique. Method: By using beta-delayed charged-particle spectroscopy of $^{12}\mathrm{N}$ using the TexAT (Texas Active Target) TPC, a high-sensitivity measurement of the direct 3 $α$ decay ratio can be performed without contributions from pile-up events. Results: A Bayesian approach to understanding the contribution of the direct components via a likelihood function shows that the direct component is $<0.043\%$ at the 95\% confidence level (C.L.). This value is in agreement with several other studies and here we can demonstrate that a small non-sequential component with a decay fraction of about $10^{-4}$ is most likely. Conclusion: The measurement of the non-sequential component of the Hoyle state decay is performed in an almost medium-free reaction for the first time. The derived upper-limit is in agreement with previous studies and demonstrates sensitivity to the absolute branching ratio. Further experimental studies would need to be combined with robust microscopic theoretical understanding of the decay dynamics to provide additional insight into the idea of the Hoyle state as an $α$-condensate.