Measurement of parity-nonconserving rotation of neutron spin in the 0.734-eV p-wave resonance of 139La
Measurement of parity-nonconserving rotation of neutron spin in the 0.734-eV p-wave resonance of 139La
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139La 0.734-eV p 波共振中中子自旋宇称非守恒旋转的测量
DOI：
10.1016/s0370-2693(02)01720-3
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发表时间：
2001
影响因子：
4.4
通讯作者：
V. Yuan
中科院分区：
文献类型：
--
作者：
T. Haseyama;K. Asahi;J. Bowman;P. Delheij;H. Funahashi;S. Ishimoto;Gordon L. Jones;A. Masaike;Y. Masuda;Y. Matsuda;K. Morimoto;Suguru Muto;S. Penttilä;V. R. Pomeroy;K. Sakai;E. Sharapov;D. Smith;V. Yuan
用中子透射法测量了~（139）La在0.734eV p波共振中的中子宇称非守恒自旋转动。两个光学极化的3 He细胞之前和之后的5厘米长的139 La的目标，每个作为一个偏振器和中子自旋分析仪。通过顺序翻转起偏器中3 He的偏振方向，仔细测量了旋转角。自旋旋转的峰峰值为（7.4±1.1）×10−3rad/cm。结果发现，与以前的实验是一致的，但结果在统计上有所改善。s-p混合模型给出弱矩阵元xW=（1.71±0.25）meV。该值与从同一共振中宇称非守恒纵向不对称性导出的值吻合得很好。
The parity nonconserving spin rotation of neutrons in the 0.734-eV p-wave resonance of139La was measured with the neutron transmission method. Two optically polarized3He cells were used before and behind a 5-cm long139La target, each as a polarizer and an analyzer for neutron spin. The rotation angle was carefully measured by flipping the direction of3He polarization in the polarizer in sequence. The peak-to-peak value of the spin rotation was determined to be (7.4±1.1)×10−3rad/cm. The result is found to be consistent with the previous experiments, but the result was statistically improved. The s–p mixing model gives the weak matrix element as xW=(1.71±0.25) meV. The value agrees well with the one deduced from the parity-nonconserving longitudinal asymmetry in the same resonance.