论文标题
$^1S_0的测量$中子中子中子有效范围
Measurement of the $^1S_0$ neutron-neutron effective range in neutron-deuteron breakup
论文作者
论文摘要
我们报告了Neutron-neutron Quasifree散射中Neutron-Deuteron Breakup中的$^{1} S_ {0} $中子 - 中子有效范围参数（$ r_ {nn} $）的最精确确定。该实验设置利用了15.5 MeV中子的准直光和八个中子检测器的阵列，该探测器位于对几个准散射运动学构型敏感的角度敏感的角度。从分解反应中发出的两个中子被检测到巧合，并使用飞行时间技术来确定它们的能量。梁目标光度的亮度是基于中子弹性散射的产率的原位。使用CD BONN核子核素电位的严格FADDEEV型计算适合我们的横截面数据，以确定$ r_ {nn} $的值。使用半社会空间正规化n $^4 $ lo $^+$手性相互作用潜力重复分析。我们获得了$ r_ {nn} = 2.86 \ pm 0.01 \，（stat）\ pm 0.10 \，（sys）$ fm和$ r_ {nn} = 2.87 \ pm 0.01 \，（stat）\ pm 0.10 \，（sys）$ fm使用CD BONN和N $ LO $^4 $^$^$^$^$^$^$^$^$^$^$ fm^fim，我们的结果与电荷对称性和先前报道的$ r_ {nn} $的值一致。
We report the most precise determination of the $^{1}S_{0}$ neutron-neutron effective range parameter ($r_{nn}$) from neutron-neutron quasifree scattering in neutron-deuteron breakup. The experiment setup utilized a collimated beam of 15.5 MeV neutrons and an array of eight neutron detectors positioned at angles sensitive to several quasifree scattering kinematic configurations. The two neutrons emitted from the breakup reaction were detected in coincidence and time-of-flight techniques were used to determine their energies. The beam-target luminosity was measured in-situ with the yields from neutron-deuteron elastic scattering. Rigorous Faddeev-type calculations using the CD Bonn nucleon-nucleon potential were fit to our cross-section data to determine the value of $r_{nn}$. The analysis was repeated using a semilocal momentum-space regularized N$^4$LO$^+$ chiral interaction potential. We obtained values of $r_{nn} = 2.86 \pm 0.01 \,(stat) \pm 0.10 \,(sys)$ fm and $r_{nn} = 2.87 \pm 0.01 \,(stat) \pm 0.10 \,(sys)$ fm using the CD Bonn and N$^4$LO$^+$ potentials, respectively. Our results are consistent with charge symmetry and previously reported values of $r_{nn}$.
