Study of Kaon Decay to Two Pions

TL;DR

This paper investigates the weak decay of kaons into two pions using the NJL model, highlighting the significant role of the \

Contribution

It introduces a detailed calculation of decay amplitudes including \

Findings

5% of the I=0 amplitude is from 5% of the I=0 amplitude is from \

The 5% of the I=0 amplitude is from \

The 5% of the I=0 amplitude is from \

Abstract

The weak decay of the kaon to two pions is studied within the NJL Model. Using the standard effective weak Hamiltonian, both the decay amplitude arising from an intermediate state \sigma-meson and the direct decay amplitude are calculated. The effect of final state interactions is also included. When the matching scale is chosen such that the decay amplitude with isospin I=2 is close to its experimental value, the \sigma-meson contributes more than 85% of the total I=0 amplitude. This supports recent suggestions that the \sigma-meson should play a vital role in explaining the \Delta I= 1/2 rule in this system.