Welcome to TWIST

The TRIUMF Weak Interaction Symmetry Test

TRIUMF experiment E614

Information for the general public

Who we are, and what we're doing.
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TWIST is an experiment which is designed to measure the decay distributions of polarized muons to high precision. Distributions which are differential in energy and angle will be determined to a precision of parts in 10,000, allowing a determination of the parameters of the standard model which characterize the muon decay to a precision 3 to 10 times higher than previously achieved. The ultimate interest motivating the experiment is the need to better understand the left-right asymmetry of the weak interaction which has been artificially incorporated into the standard model.


August 2011
Final results for the muon decay P_mu_xi are published: Phys. Rev. D.84 (2011)205121.
May 2011
Final results for the Longitudinal muon spin relaxation in high-purity aluminum and silver are published: Phys. Rev. B.83 (2011)205121
January 2011
Final results for the muon decay parameters are published (open acess): Phys. Rev. Lett. 106, 041804(2011). Archival papers are being written.
TWIST's last students, Bueno, Hillairet, and Bayes, successfully defend their theses and find paid employment in physics.
October 2009
A paper was published in Physical Review D describing our measurement of the negative muon decay energy distribution for a pure aluminum target. For the first time in any target, the precision shows effects that can be attributed to radiative corrections (preprint).

July 2008
A paper on our most recent measurements of the rho and delta parameter in muon decay has been published (open access) in Physical Review D (preprint).

August 2007
After another long data taking run, the last data were taken with the TWIST spectrometer. The experiment shifted focus to analysis.The spectrometer has been dismantled.

Last modified: Sun Aug 14 12:37:27 PDT 2011

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