Further search for the decay K+→π+ν(ν)over-bar

A search for additional evidence for the rare kaon decay K+ --> pi(+)nu<(nu)over bar> has been made with a new data set comparable in sensitivity to the previous exposure that produced a single event. No new events were found in the pion momentum region examined, 211 < P < 229 MeV/c. Including a reanalysis of the original data set, the backgrounds were estimated to contribute 0.08 +/- 0.02 events. Based on one observed event, the new branching ratio is B(K+ --> pi(+)nu<(nu)over bar>) = 1.5(-1.2)(+3.4) x 10(-10).