Chiral Algebra, Chiral Breakdown, andξParameter ofKl3Decay

Abstract

Using hard-meson current algebra with single meson dominance of currents and the $\sigma$ commutator, it is deduced that (a) the $0^{\pm }$ mesons must occur in nonets, and (b) chiral symmetry is broken by only $(3,3^{*})\oplus (3^{*},3)$ terms (which then implies a small $\xi$ parameter). Recent calculations which obtain a large negative $\xi$ with only (3,$3^{*}$) terms are seen to imply a violation of the current-algebra constraints. However, the large experimental $\xi$ can be obtained by including additional nonpole $(1,8)\oplus (8,1)$ breaking terms.