Precision Beta-Decay Studies in the Mirror Systems of <sup>8</sup>Li and <sup>8</sup>B

ORAL

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. Tensor currents were searched through a measurement of the beta-neutrino angular correlation coefficient abn in the beta-delayed alpha decays of 8Li and 8B. These decays were studied with the Beta-decay Paul Trap (BPT) at the ATLAS facility of Argonne National Laboratory. The BPT traps a cloud of ions at rest in a volume of ~1 mm3 for extended periods of time, allowing for a backing-free measurement of the emitted particles. The trapping volume is surrounded by segmented, 1mm thick DSSDs, from which the decay kinematics can be fully constrained by a b-a-a triple coincidence measurement. This enables both a nearly background-free measurement of the b-n angular correlation coefficient abn. We will present the first measurement of abn in 8B and a novel method to constrain CT and C’T in the decay of mirror systems.

*We acknowledge the U.S. DOE Contract No. DE-AC02-06CH11357 [ANL] and DE- AC52-07NA27344 [LLNL], the Argonne National Laboratory ATLAS facility, which is a DOE Office of Science User Facility, and NSERC, Canada, Contract Nos. SAPPJ-2015- 00034 and SAPPJ-2018-00028.

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Publication: Burkey, M. T. et al., Improved Limit on Tensor Currents in the Weak Interaction from 8Li β Decay. Physical Review Letters 128, 202502 (2022)
Sargsyan, G. H. et al., Impact of Clustering on the 8Li β Decay and Recoil Form Factors. Physical Review Letters 128, 202503 (2022)
Gallant, A. T. et al., Angular Correlations in the β Decay of 8B: First Tensor-Current Limits from a Mirror-Nucleus Pair. Physical Review Letters 130, 192502 (2023)

Presenters

  • Aaron T Gallant

    • Lawrence Livermore National Laboratory
    • Lawrence Livermore Natl Lab

Authors

  • Aaron T Gallant

    • Lawrence Livermore National Laboratory
    • Lawrence Livermore Natl Lab

  • Mary T Burkey

    • Lawrence Livermore National Laboratory

  • Guy Savard

    • Argonne National Laboratory

  • Nicholas D Scielzo

    • Lawrence Livermore National Laboratory

  • Jason A Clark

    • Argonne National Laboratory

  • Maxime Brodeur

    • University of Notre Dame

  • Daniel Burdette

    • Argonne National Laboratory

  • Tsviki Y Hirsh

    • Soreq Nuclear Research Center
    • Soreq NRC

  • Kay Kolos McCubbin

    • Lawrence Livermore Natl Lab
    • Lawrence Livermore National Laboratory

  • Bernhard Maass

    • Argonne National Laboratory

  • Scott T Marley

    • Louisiana State University

  • Peter Mueller

    • Argonne National Laboratory

  • Dipanwita Ray

    • University of Manitoba

  • Kevin Siegl

    • University of Tennessee

  • Kumar S Sharma

    • University of Manitoba
    • U. Manitoba

  • Louis Varriano

    • University of Chicago