$K \to 2 π$ Decay in the Nambu-Jona-Lasinio Model

Abstract

We study the $K \to 2 π$ decays using the $U_L(3) \times U_R(3)$ version of the Nambu-Jona-Lasinio model with the effective $ΔS = 1$ nonleptonic weak interaction. The $ΔI = {3/2}$ amplitude is in reasonable agreement with experimental data. On the other hand, the calculated $ΔI = {1/2}$ amplitudes strongly depend on the mass of the low-lying scalar-isoscalar $σ$ meson, and therefore give a strong constraint on the parameters of the model.

10 pages, 3 Postscript figures, Talk given at YITP Workshp: From Hadronic Matter to Quark Matter: Evolving View of Hadronic Matter, Kyoto, Japan, Oct. 30-Nov. 1, 1994, to be published in Prog. Theor. Phys. Suppl