Effective Weak Chiral Lagrangian from the Instanton Vacuum

TL;DR

This paper derives the effective weak chiral Lagrangian using an instanton-based chiral quark model, accurately determining low energy constants and explaining the $ riangle T=1/2$ enhancement through momentum-dependent quark masses.

Contribution

It introduces a novel approach to calculating the weak chiral Lagrangian constants incorporating momentum-dependent quark masses within the instanton model.

Findings

Accurate determination of $g_8$ and $g_{27}$ constants.

Improved low energy constants due to momentum dependence.

Explanation of $ riangle T=1/2$ enhancement.

Abstract

We present in this talk the recent investigation of the effective weak chiral Lagrangian within the framework of the instanton-induced chiral quark model. The low energy constants in leading order $g_8$ and $g_{27}$, and their ratio are determined. The momentum-dependence of the constituent quark mass turns out to improve the low energy constants to the great extent, respecting the $\Delta T=1/2$ enhancement.