Experiment E949 at Brookhaven National Laboratory has observed three new
events consistent with the decay K+ => pi+,nu,nubar in the pion momentum region
140 < P_pi < 199 MeV/c in an exposure of 1.71e12 stopped kaons with an
estimated total background of 0.93+-0.17(stat.)+0.32-0.24(syst.) events. This
brings the total number of observed K+ => pi+,nu,nubar events to seven.
Combining this observation with previous results, assuming the pion spectrum
predicted by the standard model, results in a branching ratio of
(1.73+1.15-1.05)e-10. An interpretation of the results for alternative models
of the decay K^ => pi+,nothing is also presented.Comment: Submitted to Phys.Rev.