A Study of the Radiative KL->pi nu e (g) Decay and Possible Osservation of Direct Photon Emission with the KLOE Detector

TL;DR

This paper reports a precise measurement of the radiative decay ratio and the first estimate of direct photon emission contribution in the KL->pi nu e gamma decay using data from the KLOE detector, providing insights into rare kaon decay processes.

Contribution

It presents the first measurement of direct emission contribution in KL radiative decay and refines the decay ratio using extensive data from the KLOE experiment.

Findings

Measured decay ratio R = (924 ± 23_stat ± 16_syst)×10^{-5}.

Estimated direct emission parameter X = -2.3 ± 1.3_stat ± 1.4_syst.

Provided the first experimental estimate of direct photon emission in this decay.

Abstract

We present the measurement of the ratio R = \frac{\Gamma(\keg;\Estar>30\mev,\qstar>20^\circ)}{\Gamma(\kegf)} and a first measurement of the direct emission contribution for the same process. We use 328 pb^{-1} of data collected at \kloe in 2001 and 2002, corresponding to about 3 million of \kegf events and about 9 thousand \keg radiative events. Our result is R= (924 \pm 23_{stat} \pm 16_{syst})10^{-5} for the branching ratio and X =-2.3\pm 1.3_{stat}\pm 1.4_{syst} for the parameter describing direct emission.