D. A. Bryman

Further evidence for the decay K+ ---> pi+ neutrino anti-neutrino

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}.

Further Evidence for the DecayK+→π+νν¯

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}.

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.

Improved measurement of the K+ ---> pi+ nu anti-nu branching ratio

An additional event near the upper kinematic limit for K+ to pi+ nu nubar has been observed by Experiment E949 at Brookhaven National Laboratory. Combining previously reported and new data, the branching ratio is B(K+ to pi+ nu nubar)= 1.47 (+1.30, - 0.89) x 10-10 based on three events observed in the pion momentum region 211<P<229 MeV/c. At the measured central value of the branching ratio, the additional event had a signal-to-background ratio of 0.9.

New measurement of the K+-->pi+ nunu branching ratio.

A.V. Artamonov, B. Bassalleck, B. Bhuyan, ∗ E.W. Blackmore, D.A. Bryman, S. Chen, 4 I-H. Chiang, I.-A. Christidi, † P.S. Cooper, M.V. Diwan, J.S. Frank, T. Fujiwara, J. Hu, J. Ives, D.E. Jaffe, S. Kabe, S.H. Kettell, M.M. Khabibullin, A.N. Khotjantsev, P. Kitching, M. Kobayashi, T.K. Komatsubara, A. Konaka, A.P. Kozhevnikov, Yu.G. Kudenko, A. Kushnirenko, ‡ L.G. Landsberg, § B. Lewis, K.K. Li, L.S. Littenberg, J.A. Macdonald, § J. Mildenberger, O.V. Mineev, M. Miyajima, K. Mizouchi, V.A. Mukhin, N. Muramatsu, T. Nakano, M. Nomachi, T. Nomura, T. Numao, V.F. Obraztsov, K. Omata, D.I. Patalakha, S.V. Petrenko, R. Poutissou, E.J. Ramberg, G. Redlinger, T. Sato, T. Sekiguchi, T. Shinkawa, R.C. Strand, S. Sugimoto, Y. Tamagawa, R. Tschirhart, T. Tsunemi, ¶ D.V. Vavilov, B. Viren, Zhe Wang, 3 N.V. Yershov, Y. Yoshimura, and T. Yoshioka

Study of the decay K+→π+νν̄ in the momentum region 140<Pπ<199MeV/c

Experiment E949 at Brookhaven National Laboratory has observed three new events consistent with the decay K+ => pi+,nu,nubar in the pion momentum region 140 pi+,nu,nubar events to seven. Combining this observation with previous results, assuming the pion spectrum predicted by the standard model, results in a branching ratio of (1.73+1.15-1.05)e-10. An interpretation of the results for alternative models of the decay K^ => pi+,nothing is also presented.

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.

The spatial resolution of the time projection chamber at triumf

Abstract The spatial resolution of the time projection chamber at TRIUMF has been investigated. The best resolution, σ ⋍ 200 μ m , occurs at the minimum drift length and for an optimum track to anode crossing angle determined by the magnetic field. The resolution worsens for tracks crossing at larger or smaller angles and for longer drift lengths. The observed resolution is quantitatively reproduced by considering the diffusion of the drifting electrons, the track to anode crossing angle, E × B effects near the anode wire and the discrete nature of the ionization process.

Pionic 2p1s X-ray transitions in 19F and 23Na

Abstract Pi-atomic 2p1s transitions have been studied in 19 F and 23 Na. The measured energies are 195.17 ± 0.16 and 275.75 ± 0.26 keV, and the Lorentzian full-widths at half-maximum are 10.12 ± 0.74 and 12.0 ± 1.2 keV respectively. A comparison is made with optical model calculations.

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