Ab initio calculations of nuclear parity-violating moments and nuclear structure corrections for tests of fundamental symmetries

Ab initio nuclear theory describes atomic nuclei as systems of nucleons interacting by QCD-based chiral effective field theory (EFT) nucleon-nucleon and three-nucleon forces. In combination with chiral EFT electroweak currents, ab initio nuclear calculations can provide model-independent results with quantifiable uncertainties relevant for precision electroweak physics.

We will discuss large-scale calculations performed within the ab initio no-core shell model (NCSM) [1] for observables requiring a computation of the nuclear Green’s function that we construct by applying the continued fraction Lanczos algorithm [2]. We will review recent results for parity violating anapole [3], electric dipole [4], and Schiff moments in light atomic nuclei. Also, we will present ongoing effort to compute nuclear structure corrections for the extraction of the V_ud matrix element from the superallowed Fermi transition measurements [5] as well as calculations of two-photon exchange nuclear structure dependent corrections needed to extract nuclear radii from the measured X-ray spectra of muonic atoms. Finally, we will highlight recent calculations of the nuclear electric dipole polarizability of the ¹²C ground state and the first excited 2⁺ state, the latter needed to determine the 2⁺ electric quadrupole moment from Coulomb excitation experiments.

[1] B. R. Barrett, P. Navratil, J. P. Vary, Progress in Particle and Nuclear Physics 69, 131 (2013). [2] M. A. Marchisio et al., Few-Body Syst. 33, 259 (2003). [3] Y. Hao et al., Phys. Rev. A 102, 052828 (2020). [4] P. Froese and P. Navratil, Phys. Rev. C 104, 025502 (2021). [5] M. Gennari, M. Drissi, M. Gorchtein, P. Navratil, and C.-Y. Seng, arXiv:2405.19281.