Measurement of the form factors of charged kaon semileptonic decays

TL;DR

This paper reports precise measurements of the form factors in charged kaon semileptonic decays, using a large dataset collected by the NA48/2 experiment, improving upon previous results and combining different decay modes.

Contribution

It provides the most accurate measurements of charged kaon semileptonic decay form factors to date, including a combined analysis of electron and muon modes.

Findings

Improved precision in form factor measurements.

Consistent results across electron and muon decay modes.

Enhanced understanding of kaon semileptonic decay dynamics.

Abstract

A measurement of the form factors of charged kaon semileptonic decays is presented, based on $4.4 \times 10^6$ $K^\pm \to \pi^0 e^\pm \nu_e$ ($K^\pm_{e3}$) and $2.3 \times 10^6$ $K^\pm \to \pi^0 \mu^\pm \nu_{\mu}$ ($K^\pm_{\mu3}$) decays collected in 2004 by the NA48/2 experiment. The results are obtained with improved precision as compared to earlier measurements. The combination of measurements in the $K^\pm_{e3}$ and $K^\pm_{\mu3}$ modes is also presented.