Measurement of the Form-Factor Slopes for the Decay KLe3 with the KLOE Detector

TL;DR

This paper reports precise measurements of the form-factor slopes in Ke3 decays using data from the KLOE detector, providing insights into strong interaction dynamics and aiding CKM matrix element determination.

Contribution

The study presents the first detailed measurement of the K-pi vector current form-factor parameters for Ke3 decay with high statistical precision.

Findings

Measured linear form-factor slope l = (28.6 ± 0.5 ± 0.4)×10^{-3}

Measured quadratic form-factor slopes l' = (25.5 ± 1.5 ± 1.0)×10^{-3} and l'' = (1.4 ± 0.7 ± 0.4)×10^{-3}

Data corresponds to about 2 million Ke3 events

Abstract

We present a measurement of the K-pi vector current form-factor parameters for the Ke3 decay. We use 328 pb$^{-1}$ of data collected in 2001 and 2002, corresponding to about 2 million Ke3 events. Measurements of semileptonic form factors provide information about the dynamics of the strong interaction and are necessary for evaluation of the phase-space integral Ie_K needed to measure the CKM matrix element Vus for Ke3 decays. Our result is $l=(28.6\pm0.5\pm0.4)10^{-3}$ for a linear fit, and $l'=(25.5\pm1.5\pm1.0)10^{-3}$, $l''=(1.4\pm0.7\pm0.4)10^{-3}$ for a quadratic fit.