M. Ardebili

Evidence for the decay K+ ---> pi+ neutrino anti-neutrino

An event consistent with the signature expected for the rare kaon decay K+ --> pi+ nu anti-nu has been observed. In the pion momentum region examined, 211 pi+ nu anti-nu, the branching ratio is (4.2 +9.7/-3.5) x E-10.

OBSERVATION OF THE DECAY K+ PI + GAMMA GAMMA

The first observation of the decay K + ! � + is reported. A total of 31 events was observed with an estimated background of 5.1±3.3 events in the � + momentum range from 100 MeV/c to 180 MeV/c. The corresponding partial branching ratio, B(K + ! � + , 100 MeV/c < P�+ < 180 MeV/c), is (6.0±1.5{stat}±0.7{sys})×10 7 . No K + ! � + decay was observed in the � + momentum region greater than 215 MeV/c. The observed � + momentum spectrum is compared with the predictions of chiral perturbation theory.

Further search for the decay K+ ---> pi+ nu anti-nu in the momentum region P < 195-MeV/c

We report the results of a search for the decay

Observation of the decay K+ ---> pi+ mu+ mu-

K^+ \to \pi^+ \nu \bar \nu

Search for the decay K+ ---> pi+ nu anti-nu in the momentum region P(pi) less than 195-MeV/c

in the kinematic region with

Search for the decay K+--> pi + nu nu -bar.

\pi^+

Measurement of direct photon emission in K+-->pi(+)pi(0)gamma decay

momentum

Measurement of Direct Photon Emission in K{sup +}{yields}{pi}{sup +}{pi}

140<P<195

Observation of the decay K+ → π+ μ+ μ−

MeV/c using the data collected by the E787 experiment at BNL. No events were observed. When combined with our previous search in this region, one candidate event with an expected background of

Search for the rare decay K+ ---> pi+ gamma

1.22 \pm 0.24