K to \pi\pi\ hadronic matrix elements of left-right current-current operators

TL;DR

This paper calculates the hadronic matrix elements of specific four-fermion operators relevant for K to pi pi decays within the Chiral Quark Model, supporting constraints on new physics from experimental data.

Contribution

It provides the first detailed evaluation of these matrix elements within the Chiral Quark Model, confirming previous estimates used in left-right symmetry analyses.

Findings

Results align with previous TeV-scale left-right symmetry estimates

Supports strong bounds on new physics parameters from K to pi pi decays

Validates the use of the Chiral Quark Model for such matrix element calculations

Abstract

Effective \Delta S=1 four fermion operators involving left- and right-handed currents are relevant in left-right gauge extensions of the standard model and scalar extension of the Yukawa sector. They induce K to \pi\pi\ decays which are strictly constrained by experimental data, typically resulting in strong bounds on the new physics scales or parameters. We evaluate the K to \pi\pi\ hadronic matrix elements of such operators within the phenomenological framework of the Chiral Quark Model. The results are consistent with the estimates used in a previous work on TeV scale left-right symmetry, thus confirming the conclusions obtained there.