$K_{e3}$ decay studies in OKA experiment

TL;DR

This paper reports on form factor measurements in $K_{e3}$ decay from the OKA experiment, including slope parameters and alternative parametrizations, based on a large dataset of 5.25 million events.

Contribution

It provides new measurements of decay form factors and explores alternative parametrizations in $K_{e3}$ decay analysis, with results supporting the Standard Model.

Findings

Measured linear and quadratic slopes of form factor $f_{+}(t)$.

Found scalar and tensor contributions compatible with zero.

Determined pole mass $M_V$ and dispersive parameter $\Lambda_+$.

Abstract

Recent results from OKA setup concerning form factor studies in $K_{e3}$ decay are presented. About 5.25M events are selected for the analysis. The linear and quadratic slopes for the decay formfactor $f_{+}(t)$ are measured: $\lambda'_{+}=(26.1 \pm 0.35 \pm 0.28 )\times 10^{-3}$, $\lambda"_{+}=(1.91 \pm 0.19 \pm 0.14)\times 10^{-3}$. The scalar and tensor contributions are compatible with zero. Several alternative parametrizations are tried: the Pole fit parameter is found to be $M_V = 891 \pm 2.0$ MeV ; the parameter of the Dispersive parametrization is measured to be $\Lambda_+ =(24.58 \pm 0.18) \times 10^{-3}$. The presented results are considered as preliminary.