Ab initio calculations of <sup>8</sup>Li beta decay recoil form factors
ORAL · Invited
Abstract
This work discusses ab initio calculations of recoil form factors in 8Li beta decay essential for improving the sensitivity of high-precision experiments that probe the weak interaction theory. We use the symmetry-adapted no-core shell model (SA-NCSM) that utilizes emergent symmetries in nuclei to reduce the dimensionality of the model space, hence making solutions to heavier nuclei and ultra-large model spaces feasible. The large-scale calculations lead to precise prediction of recoil form factors by identifying a strong correlation between them and the 8Li ground state quadrupole moment. In addition, our calculations find a 2+ state of the alpha + alpha system that is energetically accessible to beta decay but has not been observed in the experimental 8Be energy spectrum, and has an important effect on the recoil corrections and decay for the A = 8 systems.
*Supported by the U.S. NSF (PHY-1913728), Czech Science Foundation (22-14497S) and SURA. This work benefitted from computing resources provided by LSU (www.hpc.lsu.edu), the National Energy Research Scientific Computing Center (NERSC) and Frontera computing project at TACC. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. (LLNL-ABS-836801)
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Publication: Impact of Clustering on the 8Li β Decay and Recoil Form Factors, Physical Review Letters 128 (20), 202503 (2022)
Improved Limit on Tensor Currents in the Weak Interaction from 8Li β Decay, Physical Review Letters 128 (20), 202502 (2022)
Presenters
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Grigor H Sargsyan
- Lawrence Livermore National Laboratory