Quantum Monte Carlo calculations of electroweak transition matrix elements in A = 6,7 nuclei

TL;DR

This paper employs Green's function Monte Carlo methods with realistic nuclear interactions to calculate electroweak transition matrix elements in light nuclei, achieving results that largely agree with experimental data.

Contribution

It introduces a detailed Monte Carlo approach for off-diagonal electroweak matrix elements in A=6,7 nuclei using advanced nuclear interactions.

Findings

Good agreement with experimental data for most transitions

Accurate extrapolation of matrix elements from mixed estimates

Effective use of Argonne v18 and Illinois-2 interactions

Abstract

Green's function Monte Carlo calculations of magnetic dipole, electric quadrupole, Fermi, and Gamow-Teller transition matrix elements are reported for A=6,7 nuclei. The matrix elements are extrapolated from mixed estimates that bracket the relevant electroweak operator between variational Monte Carlo and GFMC propagated wave functions. Because they are off-diagonal terms, two mixed estimates are required for each transition, with a VMC initial (final) state paired with a GFMC final (initial) state. The realistic Argonne v18 two-nucleon and Illinois-2 three-nucleon interactions are used to generate the nuclear states. In most cases we find good agreement with experimental data.