Measurement of the Michel Parameter xi" in Polarized Muon Decay and Implications on Exotic Couplings of the Leptonic Weak Interaction

Abstract

The Michel parameter xi" has been determined from a measurement of the longitudinal polarization of positrons emitted in the decay of polarized and depolarized muons. The result, xi" = 0.981 +- 0.045stat +- 0.003syst, is consistent with the Standard Model prediction of unity, and provides an order of magnitude improvement in the relative precision of this parameter. This value sets new constraints on exotic couplings beyond the dominant V-A description of the leptonic weak interaction.

arXiv comment15 pages, 16 figures, 3 tables; submitted to Phys. Rev. D

References in corpus (4)

• Muon Decay and Physics Beyond the Standard Model
• Superallowed 0+ to 0+ nuclear beta decays: A new survey with precision tests of the conserved vector current hypothesis and the standard model
• Precise measurement of parity violation in polarized muon decay
• Precision muon decay measurements and improved constraints on the weak interaction

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