First direct constraints on Fierz interference in free-neutron β decay
First direct constraints on Fierz interference in free-neutron β decay
复制标题
首次直接限制自由中子 β 衰变中的 Fierz 干涉
DOI：
10.1103/physrevc.96.042501
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发表时间：
2017
影响因子：
3.1
通讯作者：
B. Zeck
中科院分区：
文献类型：
--
作者：
K. Hickerson;X. Sun;Y. Bagdasarova;D. Bravo;L. Broussard;M. Brown;R. Carr;S. Currie;X. Ding;B. Filippone;A. Garc'ia;P. Geltenbort;J. Hoagland;A. Holley;R. Hong;T. Ito;A. Knecht;C;J. Liu;M. Makela;R. Mammei;J. Martin;D. Melconian;M. Mendenhall;S. Moore;C. Morris;R. Pattie;Jr.;A. Galv'an;R. Picker;M. Pitt;B. Plaster;J. Ramsey;R. Rios;A. Saunders;S. Seestrom;E. Sharapov;W. Sondheim;E. Tatar;R. Vogelaar;B. Vorndick;C. Wrede;A. Young;B. Zeck
自由中子β衰变的精确测量已经被用来精确地限制我们对弱相互作用的理解。然而，中子Fierz干涉项B_n，这是特别敏感的超标准模型张量电流在TeV尺度，迄今为止，逃避测量。在这里，我们报告了这个项的第一个直接约束，发现B_n = 0.067 ± 0.005_（stat）^（+0.090）_（-0.061）_（sys），与标准模型一致。不确定度主要由绝对能量重建和β谱仪能量响应的线性度决定。
Precision measurements of free-neutron β decay have been used to precisely constrain our understanding of the weak interaction. However, the neutron Fierz interference term b_n, which is particularly sensitive to beyond-standard-model tensor currents at the TeV scale, has thus far eluded measurement. Here we report the first direct constraints on this term, finding b_n=0.067±0.005_(stat)^(+0.090)_(−0.061)_(sys), consistent with the standard model. The uncertainty is dominated by absolute energy reconstruction and the linearity of the β spectrometer energy response.