
Ab initio nuclear theory have reached the degree of maturity to describe the structure and electroweak interactions of atomic nuclei. This paves the way to quantitative predictions on the interaction of neutrinos with nuclei, which span broad energy and momentum regimes. This is a required input for a quantitative study of fundamental symmetries and astrophysical processes.
As an example, neutrino oscillation experiments, currently relying on oversimplified models of nuclear dynamics, demand for accurate theoretical predictions for the neutrinonucleus cross sections. In addition, the interpretation of present and planning of future neutrinoless ββ decay experiments need reliable values of the nuclear matrix elements that govern the decay. Current theoretical predictions suffer from large uncertainties, which could reach a factor of 10.
Among the highlights of our program, we find the following particularly relevant
Promising results for the structure of light nuclei and nuclear matter equation of state based on local chiral effective field theory potentials with and without explicit Delta resonances.
Test of nuclear saturation in mediummass nuclei with the selfconsistent Green's function method using new localnonlocal chiral interactions.
Beta decays of light nuclei obtained from highlysophisticated nuclear manybody approaches, such as the nocore shell model and the Green's function Monte Carlo were discussed. In particular:
An inconsistent effect of twobody currents (quenching from nocore shell model, enhancement from Green's function Monte Carlo) was identified.
The role of nuclear correlations and currents was disentangled in the analysis of the beta decay of mediummass and heavy nuclei.
Relevance of electron scattering data to constrain neutrinonucleus cross sections. Results for Ar40 (used by the DUNE experiment) and Ti48 from a recent JLab experiment have been presented.
Selfconsistent Green's Function calculations of the nuclear spectral function for Ar40 and O16, both used in neutrinooscillation detectors. Electron scattering calculations based on these spectral functions agree well with data.
A new method to extract the electroweak crosssections from Quantum Monte Carlo simulations successfully tested on He4.
Fruitful discussion on the relevance for ββ decay experiments of chargeexchange reactions. Muon capture identified as a promising path to test nuclear calculations at the momentumtransfer regime relevant for neutrinoless ββ decay.
