Quantum Monte Carlo calculations of electroweak observables*

Experiments searching for neutrinoless double beta (0νββ) decay and measuring beta decay spectra will address important questions within fundamental symmetries. To interpret new physics signals, these experiments require an accurate treatment of the underlying nuclear dynamics. Quantum Monte Carlo (QMC) methods allow one to solve the many-body Schrödinger equation while retaining the full complexity of the strongly-correlated nuclear system. Recently, QMC calculations using the Norfolk two- and three-nucleon chiral interaction and its set of consistent one- and two-body electroweak current operators have been validated with experimental data for beta decay and muon capture. In this talk, I will discuss using QMC methods with the Norfolk model to make predictions of the ⁶He beta decay spectrum and A=6 0νββ decay matrix elements. Using the various Norfolk model classes, we estimate the error on these observables arising from different choices in constructing the chiral interaction.