422 research outputs found
High Purity Pion Beam at TRIUMF
An extension of the TRIUMF M13 low-energy pion channel designed to suppress
positrons based on an energy-loss technique is described. A source of beam
channel momentum calibration from the decay pi+ --> e+ nu is also described.Comment: 5 page
Search for Free Decay of Negative Pions in Water and Light Materials
We report on a search for the free decay component of pi- stopped in water
and light materials. A non-zero value of this would be an indication of
anomalous nu_e contamination to the nu_e and nu_mu_bar production at
stopped-pion neutrino facilities. No free decay component of pi- was observed
in water, Beryllium, and Aluminum, for which upper limits were established at
8.2E-4, 3.2E-3, and 7.7E-3, respectively
Study of a Large NaI(Tl) Crystal
Using a narrow band positron beam, the response of a large high-resolution
NaI(Tl) crystal to an incident positron beam was measured. It was found that
nuclear interactions cause the appearance of additional peaks in the low energy
tail of the deposited energy spectrum
Status of the TRIUMF PIENU Experiment
The PIENU experiment at TRIUMF aims to measure the pion decay branching ratio
with precision % to provide a sensitive test of electron-muon
universality in weak interactions. The current status of the PIENU experiment
is presented.Comment: Talk presented CIPANP2015. 8 pages, LaTeX, 4 eps figure
Improved Search for Heavy Neutrinos in the Decay
A search for massive neutrinos has been made in the decay . No evidence was found for extra peaks in the positron energy spectrum
indicative of pion decays involving massive neutrinos (). Upper limits (90 \% C.L.) on the neutrino mixing matrix element
in the neutrino mass region 60--135 MeV/ were set, which are
%representing an order of magnitude improvement over previous results
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
Improved measurement of the K+->pi+nu(nu)over-bar branching ratio
An additional event near the upper kinematic limit for K+-->pi(+)nu(nu) over bar has been observed by experiment E949 at Brookhaven National Laboratory. Combining previously reported and new data, the branching ratio is B(K+-->pi(+)nu(nu) over bar)=(1.47(-0.89)(+1.30))x10(-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
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