Impact of Clustering on the Li8 β Decay and Recoil Form Factors

• Published in: Physical review letters 2022-05, Vol.128 (20)
• Main Authors: Sargsyan, G. H., Launey, K. D., Burkey, M. T., Gallant, A. T., Scielzo, N. D., Savard, G., Mercenne, A., Dytrych, T., Langr, D., Varriano, L., Longfellow, B., Hirsh, T. Y., Draayer, J. P.
• Format: Article
• Language: English
• Subjects: Alpha decay; Beta decay; Electroweak interactions in nuclear physics; Nuclear many-body theory; NUCLEAR PHYSICS AND RADIATION PHYSICS; Nuclear structure & decays; PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
• ISSN: 0031-9007; 1079-7114

We place unprecedented constraints on recoil corrections in the β decay of 8Li, by identifying a strong correlation between them and the 8Li ground state quadrupole moment in large-scale ab initio calculations. The results are essential for improving the sensitivity of high-precision experiments that probe the weak interaction theory and test physics beyond the standard model. In addition, our calculations predict a 2+ state of the α + α system that is energetically accessible to β decay but has not been observed in the experimental 8Be energy spectrum, and has an important effect on the recoil corrections and β decay for the A = 8 systems. Furthermore, this state and an associated 0+ state are notoriously difficult to model due to their cluster structure and collective correlations, but become feasible for calculations in the ab initio symmetry-adapted no-core shell-model framework.