Precision Beta-Decay Studies of <sup>8</sup>Li and <sup>8</sup>B to Constrain Tensor Currents in the Weak Interaction
ORAL · Invited
Abstract
The weak interaction of the Standard Model is well-described by a vector-axial vector, or ‘V-A’, structure, which reproduces both maximal parity violation and left-handed neutrinos in beta-decay. However, there is no first-principles reason that other the interactions, such as scalar (S) or tensor (T), may not be present. The existence of these exotic S and T currents can then be probed through their effect on various β-decay correlations, such as the β-ν angular correlation coefficient aβν and the Fierz interference term bF. The Gamow-Teller β-decays of 8Li and 8B are ideal to probes to measure aβν due to their large Q-values and the delayed alpha emission from the excited state 8Be, allowing for a detailed measurement of the kinematic shift between the two fragments which can be used to determine aβν. These measurements were performed with the Beta decay Paul Trap (BPT) at Argonne National Lab. The BPT is surrounded on 4 sides with double-sided silicon strip detectors backed by plastic scintillator detectors, which allow the kinematics of decay products from the trapped mass-8 ions to be over-constrained. In this presentation we will present the recent results from our work in 8Li and first results from the decay of 8B.
*We acknowledge NSERC, Canada, App. No. 216974, the U.S. DOE Contract No. DE-AC02- 06CH11357 [ANL] and DE-AC52-07NA27344 [LLNL], NSF grant no. 1144082 and the ANL ATLAS facility.
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Publication: M. G. Sternberg et al., Phys. Rev. Lett. 115, 182501; M. T. Burkey et al., Phys. Rev. Lett. 128, 202502; G. H. Sargsyan et al., Phys. Rev. Lett. 128, 202503; A. T. Gallant et al., To be submitted to PRL; B. Longfellow et al., To be submitted to PRL
Presenters
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Aaron T Gallant
- Lawrence Livermore National Laboratory
- Lawrence Livermore Natl Lab