An upper limit on the branching ratio for the decay K+→π+νν ̄ is set at 7.5 × 10-9 (90% C.L.) using the kinematic region above the Kπ2 (K+→π+π0) peak. When combined with our result from below the Kπ2 peak, we obtain the limit 5.2 × 10-9. An upper limit of 1.7 × 10-9 is also found on the branching ratio for decays of the form K+→π+X0 where X0 is any massless, weakly interacting neutral particle. Limits are also set for cases where MX0>0.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)