387 research outputs found
Measurement of Direct Photon Emission in K^+ -> pi^+ pi^0 gamma Decay
We have performed a measurement of the K^+ -> pi^+ pi^0 gamma decay and have
observed 2 X 10^4 events. The best fit to the decay spectrum gives a branching
ratio for direct photon emission of (4.7\pm0.8\pm0.3) X 10^{-6} in the pi^+
kinetic energy region of 55 to 90 MeV and requires no component due to
interference with inner bremsstrahlung.Comment: 9 pages, 3 figures. To be submitted to PR
Further Evidence for the Decay K+ to pi+ neutrino-antineutrino
Additional evidence for the rare kaon decay K+ to pi+ neutrino-antineutrino
has been found in a new data set with comparable sensitivity to the previously
reported result. One new event was observed in the pion momentum region
examined, 211<P<229 MeV/c, bringing the total for the combined data set to two.
Including all data taken, the backgrounds were estimated to contribute 0.15 pm
0.05 events. The branching ratio is B=1.57^{+1.75}_{-0.82} 10^{-10}.Comment: 10 pages, 2 figure
Search for the decay in the momentum region
We have searched for the decay in the kinematic
region with pion momentum below the peak. One event was
observed, consistent with the background estimate of . This
implies an upper limit on
(90% C.L.), consistent with the recently measured branching ratio of
, obtained using the standard model
spectrum and the kinematic region above the peak. The
same data were used to search for , where is a weakly
interacting neutral particle or system of particles with .Comment: 4 pages, 2 figure
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