Anomalous chiral perturbation theory meson Lagrangian to orderp6reexamined

We present a revised and extended construction of the mesonic Lagrangian density in chiral perturbation theory (ChPT) at order ${p}^{6}$ in the anomalous (or epsilon) sector, ${\mathcal{L}}_{6,\ensuremath{\epsilon}}.$ After improving several aspects of the strategy we used originally, i.e., a more efficient application of partial integration, the implementation of so-called Bianchi identities, and additional trace relations, we find the new monomial sets to include 24 ${SU(N}_{f}),$ 23 $\mathrm{SU}(3),$ and 5 $\mathrm{SU}(2)$ elements. Furthermore, we introduce 8 supplementary terms due to the extension of the chiral group to ${SU(N}_{f}{)}_{L}\ifmmode\times\else\texttimes\fi{}{SU(N}_{f}{)}…