Angular Correlations in the β Decay of ^{8}B: First Tensor-Current Limits from a Mirror-Nucleus Pair

Area of Science:

• Nuclear Physics
• Particle Physics
• Standard Model Physics

Background:

• The Standard Model of particle physics describes fundamental forces and particles.
• Gamow-Teller decays are crucial for understanding nuclear structure and weak interactions.
• Previous measurements of beta decay angular correlations have provided insights into fundamental symmetries.

Purpose of the Study:

• To perform the first measurement of the alpha-beta-neutrino angular correlation in the Gamow-Teller beta-plus decay of Boron-8.
• To test the predictions of the V-A electroweak interaction within the Standard Model.
• To search for evidence of exotic weak interaction currents beyond the Standard Model.

Main Methods:

• Utilized the Beta-decay Paul Trap for high-precision measurements.
• Expanded upon techniques developed for previous studies of Lithium-8 beta-minus decay.
• Analyzed angular correlation data to constrain contributions from hypothetical tensor currents.

Main Results:

• The measured angular correlation in Boron-8 decay is consistent with the V-A electroweak interaction.
• Established a stringent upper limit on the ratio of tensor to axial-vector currents: |C_{T}/C_{A}|^{2}<0.013 at 95.5% confidence.
• Achieved the first high-precision angular correlation measurements in mirror decays using an ion trap.

Conclusions:

• The results support the Standard Model's description of electroweak interactions.
• The study demonstrates a novel pathway for enhancing precision in searches for physics beyond the Standard Model.
• Combining data from Boron-8 and Lithium-8 decays offers increased sensitivity to exotic currents.