412 research outputs found
Precision Measurement of the π+→e+νe Branching Ratio in the PIENU Experiment
The PIENU experiment at TRIUMF aims to measure the branching ratio of the pion decay modes Rπ=[π+→e+νe(γ)]/[π+→μ+νμ(γ)] with precision of <0.1%.
Precise measurement of RÏ€ provides a stringent test of electron-muon universality in weak interactions. The current status of the PIENU experiment and future prospects are presented
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
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
Estimate of B(K -> pi nu nubar) from Standard Model fits to lambda_t
We estimate B(K -> pi nu nubar) in the context of the Standard Model by
fitting for lambda_t = Vtd x V*ts of the `kaon unitarity triangle' relation. We
fit data from epsilon_K, the CP-violating parameter describing K-mixing, and
a_{psi K}, the CP-violating asymmetry in B -> J/psi K decays. Our estimate is
independent of the CKM matrix element Vcb and of the ratio of Bs to Bd mixing
frequencies. The measured value of B(K+ -> pi+ nu nubar) can be compared both
to this estimate and to predictions made from the ratio of B mixing
frequencies.Comment: 8 pages, including 6 figures. v3 includes an expanded discussion of
correlations between SM inputs to the lambda_t fit, clarifies the discussion
of the independence of this result from the ratio of B mixing frequencies,
includes minor updates to the values of SM input parameters, and includes
some new and some updated reference
Physics at a Fermilab Proton Driver
This report documents the physics case for building a 2 MW, 8 GeV
superconducting linac proton driver at Fermilab.Comment: 52 pages, 15 figure
Search for the rare decays and
The rare pion decays
and are allowed in the
Standard Model but highly suppressed. These decays were searched for using data
from the PIENU experiment. A first result for
,
and an improved measurement
were obtained.Comment: 6 figure
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