T. F. Kycia

Absorption cross section of π±, K±, p and p on nuclei between 60 and 280 GeV/c

Abstract Absorption cross sections of π±, K±, p and p have been measured on targets of Li, C, Al, Cu, Sn and Pb at 60, 200, and 280 GeV/c.

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.

Further search for the decay K+-->pi(+)nunu;

A search for additional evidence for the rare kaon decay K^+ -->pi^+ nu nubar has been made with a new data set comparable in sensitivity to the previous exposure that produced a single event.A search for additional evidence for the rare kaon decay K{sup +}{yields}{pi}{sup +}{nu}{nu} (bar sign) 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{sup +}{yields}{pi}{sup +}{nu} {nu}(bar sign))=1.5{sup +3.4}{sub -1.2}x10{sup -10} . (c) 2000 The American Physical Society.

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 in the momentum region Pπ<195 MeV/c

in the kinematic region with

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

\pi^+

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

momentum

Measurement of π±, K±, p and p production by 200 and 300 GeV/c protons

140<P<195