Recent KLOE results on radiative kaon decays

TL;DR

The KLOE collaboration measured radiative kaon decay processes, confirming chiral perturbation theory predictions and reducing uncertainties in fundamental kaon decay ratios, with detailed spectral analysis of emitted photons.

Contribution

This study provides new experimental data on radiative kaon decays, validating chiral perturbation theory and contrasting with light front quark model predictions.

Findings

Measured the ratio of Ke2γ decay width to inclusive Kμ2(γ) width.

Observed radiation spectrum agrees with chiral perturbation theory.

Analyzed photon energy and angle distributions to study interference effects.

Abstract

While measuring the ratio R_K = \Gamma(K+e2(\gamma))/\Gamma(K+\mu2(\gamma)), the KLOE Collaboration has studied the radiative process Ke2\gamma. The ratio of the width for the Ke2\gamma decay with a positively polarized photon from structure-dependent radiation to the inclusive K\mu2(\gamma) width is found to be 1.484(68) 10-5. The observed radiation spectrum agrees with predictions from chiral perturbation theory and is in contrast with predictions based on the light front quark model. This result reduces the contribution to systematic uncertainties on measurements of R_K. In a separate study, KLOE has measured the ratio of the radiative Ke3\gamma decay width to the inclusive Ke3(\gamma) width to be 924(28) 10-5. The distribution in energy and angle of the radiative photon has been analyzed in an attempt to isolate the signature from interference of the inner-bremsstrahlung and structure-dependent amplitudes.