Nuclear Axial Currents in Chiral Effective Field Theory

Understand

Two-nucleon axial charge and current operators are derived in chiral effective field theory up to one loop.

• The derivation is based on time-ordered perturbation theory, and accounts for cancellations between the contributions of irreducible diagrams and the contributions due to non-static corrections from energy denominators of reducible diagrams.
• Ultraviolet divergencies associated with the loop corrections are isolated in dimensional regularization.
• The resulting axial current is finite and conserved in the chiral limit, while the axial charge requires renormalization.