$K_{e3}$ decay studies in OKA experiment

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: ${\lambda }_{+}^{\mathrm{\prime }}=(26.1\pm 0.35\pm 0.28)\times {10}^{-3}$, $\lambda"{+}=(1.91 \pm 0.19 \pm 0.14)\times 10^{-3}$. 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.