Study of three-body charged decays ofKL0

An experiment using a wire-chamber magnetic spectrometer was performed at SLAC to obtain the form factors for $K_L^0$ decays. This experiment was designed to measure efficiently all three major decay modes $K_{3\pi }$, $K_{e3\mathrm{}}$, and $K_{\mu 3}$ simultaneously. For the $K_{3\pi }$ decay, we measured the slope parameter $a=-4.69\mathrm{}\pm 0.17$. We find for the semileptonic modes $K_{e3\mathrm{}}$ and $K_{\mu 3}$ that ${\lambda }_{+}=+0.044\mathrm{}\pm 0.006$, ${\lambda }_0=+0.024\mathrm{}\pm 0.013$, and $\xi \mathrm{}\left(t\right)=-0.20\mathrm{}\pm 0.15$. All the uncertainties quoted above include systematic effects.