Chiral Symmetry in Nuclei

Abstract

The impact of chiral symmetry on nuclear physics is discussed in the context of recent advances in the few-nucleon systems and of dimensional power counting. The tractability of few-nucleon calculations, illustrated by very recent solutions for $A = 2-6$, is shown to follow from power counting based on chiral Lagrangians. The latter predicts the suppression of $N$-body forces, as originally shown by Weinberg. Isospin violation in the nuclear force is similarly analyzed using the results of van Kolck, and this is shown to be consistent with results from the Nijmegen phase-shift analysis. Conventional $ρ- ω$ and $π- η$ mixing models with on-shell mixing strength are not inconsistent with naive power counting. Meson-exchange currents calculated in chiral perturbation theory are in good agreement with experiment.