Limit on Tensor Currents from ^{8}Li β Decay.

Area of Science:

• Nuclear Physics
• Particle Physics
• Standard Model Physics

Background:

• The standard model of particle physics describes the weak interaction with a vector-axial-vector (V-A) structure.
• Previous limits on tensor currents in nuclear beta decay relied on a half-century-old measurement.
• A comprehensive understanding of fundamental interactions requires precise experimental verification.

Purpose of the Study:

• To experimentally investigate the V-A structure of the weak interaction.
• To place stringent limits on tensor currents in nuclear beta decay.
• To independently verify previous findings using a different nuclear system and advanced techniques.

Main Methods:

• Measurement of the beta-neutrino-alpha correlation in the beta decay of Lithium-8.
• Analysis of the subsequent alpha-particle breakup of the Beryllium-8 daughter nucleus.
• Utilizing modern ion-trapping techniques to minimize systematic uncertainties.

Main Results:

• Experimental results are consistent with a purely V-A interaction.
• The tensor fraction of couplings to right-handed neutrinos was limited to |C_{T}/C_{A}|^{2}<0.011 (95.5% confidence level).
• The findings corroborate the results obtained from Helium-6 beta decay.

Conclusions:

• The study provides strong experimental support for the V-A structure of the weak interaction.
• The precise limits on tensor currents enhance our understanding of fundamental particle interactions.
• Modern experimental methods offer improved accuracy and reduced systematic errors in nuclear decay studies.