Search for right-handed currents in muon decay

Journal Article · Wed Oct 01 00:00:00 EDT 1986 · Phys. Rev. D; (United States)

DOI:https://doi.org/10.1103/PhysRevD.34.1967· OSTI ID:5146049

Jodidio, A; Balke, B; Carr, J; Gidal, G; Shinsky, K A; Steiner, H M; Stoker, D P; Strovink, M; Tripp, R D; Gobbi, B

Limits are reported on charged right-handed currents, based on precise measurement of the end-point e/sup +/ spectrum in ..mu../sup +/ decay. Highly polarized ..mu../sup +/ from a TRIUMF ''surface'' muon beam were stopped in pure metal foil and liquid-He targets selected to minimize depolarization effects. In the stopping target region either a spin-precessing transverse field (70 or 110 G) or a spin-holding longitudinal field (0.3 or 1.1 T) was applied. Data collected with the spin-precessing field were used for the momentum calibration of the spectrometer. The spin-held data were used to measure the relative e/sup +/ rate at the momentum end point in a direction opposite to the ..mu../sup +/ spin. In terms of the standard muon-decay parameters this rate is given by (1-xiP/sub ..mu../delta/rho) where P/sub ..mu../ is the muon polarization. The combined 90% confidence lower limit from the analysis presented in this paper and our earlier analysis of the spin-precessed data by means of the muon-spin-rotation (..mu..SR) technique is xiP/sub ..mu../delta/rho>0.9975. For models with manifest left-right symmetry and massless neutrinos this result implies the 90% confidence limits m(W/sub 2/)>432 GeV/c/sup 2/ and -0.050<0.035, where W/sub 2/ is the predominantly right-handed boson and zeta is the left-right mixing angle.

• Research Organization: Lawrence Berkeley Laboratory, Berkeley, CA; Univ. of California, Berkeley, CA (United States). Dept. of Physics
• DOE Contract Number: AC03-76SF00098; AC02-76ER02289
• OSTI ID: 5146049
• Journal Information: Phys. Rev. D; (United States), Vol. 34:7
• Country of Publication: United States
• Language: English

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72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
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