Positron Momentum Spectrum and Branching Ratio of Ke3+ Decay

The positron momentum spectrum and branching ratio of $K_{e3}^{+}$ decay has been remeasured in a spark chamber and counter experiment at the Princeton-Pennsylvania Accelerator. We obtain a branching ratio of (5.20\ifmmode\pm\else\textpm\fi{}0.19)%. The dominant coupling was found to be vector. Under the assumption of a real, constant form factor, with 90% confidence, admixtures greater than 4% tensor and 15% scalar coupling are excluded by the positron momentum spectrum of 4638 events; limits of 7% tensor and 5% scalar are set by 1393 previously reported events in which the ${\ensuremath{\pi}}^{0}$ was detected in addition to the positron.