KTeV Results on Chiral Perturbation Theory

TL;DR

The KTeV experiment measured rare kaon decay rates to test chiral perturbation theory at O(p^6), providing precise branching ratios and limits that improve upon previous results.

Contribution

This paper presents new, precise measurements of rare kaon decay branching ratios, offering stringent tests of chiral perturbation theory at higher order.

Findings

Measured BR(KL-> pi0 pi0 gamma) = (1.30 +/- 0.03 +/- 0.04)E-6

Measured BR(KL-> pi0 e+ e- gamma) = (1.90 +/- 0.16 +/- 0.12)E-8

Set upper limit BR(KL->pi0 pi0 gamma)< 2.32E-7

Abstract

The KTeV experiment has carried out a broad program of studies of rare kaon decays. In this paper we present results on KL -> pi0 gamma gamma, KL -> pi0 e+ e- gamma and KL -> pi0 pi0 gamma. These decays provide a window for testing chiral perturbation theory at O(p^6). We find BR(KL-> pi0 pi0 gamma) = (1.30 +/- 0.03 +/- 0.04)E-6, BR(KL-> pi0 e+ e- gamma) = (1.90 +/- 0.16 +/- 0.12)E-8, and set the limit BR(KL->pi0 pi0 gamma)< 2.32E-7. The KTeV measurements are competitive with or better than the world's best results in these decays.