论文标题
$^{12} $ c（p，p，p'）的高精度质子角分布测量值确定$ e0 $衰减的分支比
High precision proton angular distribution measurements of $^{12}$C(p,p') for determination of the $E0$ decay branching ratio of the Hoyle state
论文作者
论文摘要
背景：在恒星中，仅通过$3α$工艺生产碳，其中三个$α$颗粒融合以形成$^{12} $ c在兴奋的Hoyle状态下，然后可以腐烂到基态。恒星中的碳产量速率取决于霍伊尔状态的辐射宽度。可以通过组合三个单独测量的数量来推导辐射宽度，其中之一是$ e0 $衰减的分支比率。 $ e0 $分支比率可以通过在$^{12} $ c $（p，p，p'）$反应中激发Hoyle State的分支比例来衡量，并测量其Hoyle State的一对衰减和第一个$ 2^+$ state。 目的：通过测量Hoyle State人群（$ 0^+_ 2 $）和$ 2^+_ 1 $ state in $^{12} $ c in $^{12} $ C $ C $（P，P，P，P'）$ nesties $ nesties $在10.20和10.20 mev之间，$^{12} $ C in $^{12} $ c in $^{12} $ c in $ n of 10.20和10.70 mev car霍伊尔州。 Method: Proton angular distributions populating the ground, first $2^+$, and the Hoyle states in $^{12}$C were measured in $^{12}$C(p,p') reactions with a silicon detector array covering $22^\circ<θ<158^\circ$ in 14 energy steps between 10.20 and 10.70 MeV with a thin ($60\ μ$ g/cm $^2 $）$^{nat} $ c目标。 结果：提取每个状态的总横截面，并在每个能量步骤确定的$ 2^+_ 1 $和Hoyle状态之间的总体比率。通过适当平均这些横截面并采用它们的比率，可以提取适用于对配对转换测量的任何厚$^{12} $ c目标的同等种群比率。 结论：我们提供了一般数据集的高精度$^{12} $ c $（p，p，p，p'）$横截面，这使得由于$ 2^+_ 1 $和$ 0^+_ 2 $的$ 2^+_ 2 $ state的不确定性，质子不弹性散射可忽略不计的任何$ e0 $ e0 $ e0 $ $ e0 $ $ e0 $ $ e0 $ $ e0 $ $ e0 $^$^$^$^$^^$^} $^}。
Background: In stars, carbon is produced exclusively via the $3α$ process, where three $α$ particles fuse to form $^{12}$C in the excited Hoyle state, which can then decay to the ground state. The rate of carbon production in stars depends on the radiative width of the Hoyle state. The radiative width can be deduced by combining three separately measured quantities, one of which is the $E0$ decay branching ratio. The $E0$ branching ratio can be measured by exciting the Hoyle state in the $^{12}$C$(p,p')$ reaction and measuring the pair decay of its Hoyle state and first $2^+$ state. Purpose: To reduce the uncertainties in the carbon production rate in the universe by measuring a set of proton angular distributions for the population of the Hoyle state ($0^+_2$) and $2^+_1$ state in $^{12}$C in $^{12}$C$(p,p')$ reactions between 10.20 and 10.70 MeV, used in the determination of the $E0$ branching ratio of the Hoyle state. Method: Proton angular distributions populating the ground, first $2^+$, and the Hoyle states in $^{12}$C were measured in $^{12}$C(p,p') reactions with a silicon detector array covering $22^\circ<θ<158^\circ$ in 14 energy steps between 10.20 and 10.70 MeV with a thin ($60\ μ$g/cm$^2$) $^{nat}$C target. Results: Total cross-sections for each state were extracted and the population ratio between the $2^+_1$ and Hoyle state determined at each energy step. By appropriately averaging these cross-sections and taking their ratio, the equivalent population ratio can be extracted applicable for any thick $^{12}$C target used in pair-conversion measurements. Conclusions: We present a general data set of high-precision $^{12}$C$(p,p')$ cross-sections that make uncertainties resulting from the population of the $2^+_1$ and $0^+_2$ states by proton inelastic scattering negligible for any future measurements of the $E0$ branching ratio in $^{12}$C.
