R. Poutissou

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.

Radiative Muon Capture on Hydrogen and the Induced Pseudoscalar Coupling

Next to the hydrogen atom, the µ − p system is the most fundamental lepton-hadron system; therefore it can be used to test and extend our basic knowledge of the weak semi-leptonic interaction between leptons and quarks. Radiative muon capture (RMC) is much more sensitive than ordinary muon capture (OMC) to the induced pseudoscalar coupling constant of the weak semi-leptonic current because of the much larger range of momentum transfers which can occur in RMC. A status report on TRIUMF E452, Radiative Muon Capture on Hydrogen, which is anticipating a 10% measurement of this coupling constant, is presented.

Search for heavy neutrinos in K+→μ+νH decays

Evidence of a heavy neutrino, ν H , in the K + → μ + ν H decays was sought using the E949 experimental data with an exposure of 1.70 × 1 0 12 stopped kaons. With the major background from the radiative K + → μ + ν μ γ decay understood and suppressed, upper limits (90%xa0C.L.) on the neutrino mixing matrix element between the muon and heavy neutrinos, | U μ H | 2 , were set at the level of 1 0 - 7 to 1 0 - 9 for the heavy neutrino mass region 175 to 300 MeV / c 2 .

A detector to search for K+ → π+ νν

Abstract The detector built for experiment 787 to measure the decay K + → π + ν ν at Brookhaven National Laboratory is describe

Search for the decay in the momentum region Pπ<195 MeV/c

Abstract We have searched for the decay K + →π + ν ν in the kinematic region with pion momentum below the K + → π + π 0 peak. One event was observed, consistent with the background estimate of 0.73±0.18. This implies an upper limit on B(K + →π + ν ν ) −9 (90% C.L.), consistent with the recently measured branching ratio of 1.57 +1.75 −0.82 ×10 −10 , obtained using the standard model spectrum and the kinematic region above the K + → π + π 0 peak. The same data were used to search for K + → π + X 0 , where X 0 is a weakly interacting neutral particle or system of particles with 150 M X 0 c 2 .We have searched for the decay

New measurement of the K+→π+νν̄ branching ratio

K^+ to pi^+ nu barnu

Search for the decay [ital K][sup +][r arrow][pi][sup +][nu][bar [nu]]

in the kinematic region with pion momentum below the

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

K^+ to pi^+ pi^0

500-MHz transient digitizers based on GaAs CCDs

peak. One event was observed, consistent with the background estimate of

TWIST- The TRIUMF weak interaction symmetry test the Michel parameters from μ+ decay

0.73pm 0.18