Limit on Tensor Currents from Li-8 beta Decay

作者：Sternberg M G; Segel R; Scielzo N D^*; Savard G; Clark J A; Bertone P F; Buchinger F; Burkey M; Caldwell S; Chaudhuri A; Crawford J E; Deibel C M; Greene J; Gulick S; Lascar D; Levand A F; Li G; Galvan A Perez; Sharma K S; Van Schelt J; Yee R M; Zabransky B J

来源：Physical Review Letters, 2015, 115(18): 182501.

DOI：10.1103/PhysRevLett.115.182501

In the standard model, the weak interaction is formulated with a purely vector-axial-vector (V-A) structure. Without restriction on the chirality of the neutrino, the most general limits on tensor currents from nuclear beta decay are dominated by a single measurement of the beta-(nu) over bar correlation in He-6 beta decay dating back over a half century. In the present work, the beta-(nu) over bar-alpha correlation in the beta decay of Li-8 and subsequent alpha-particle breakup of the Be-8* daughter was measured. The results are consistent with a purely V-A interaction and in the case of couplings to right-handed neutrinos (C-T = -C'(T)) limits the tensor fraction to vertical bar C-T/C-A vertical bar(2) < 0.011 (95.5% C.L.). The measurement confirms the He-6 result using a different nuclear system and employing modern ion-trapping techniques subject to different systematic uncertainties.

• 出版日期2015-10-28
• 单位西北大学