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POLARIZATION OF COSMIC-RAY $mu$ MESONS: EXPERIMENT

Journal Article · · Physical Review (U.S.) Superseded in part by Phys. Rev. A, Phys. Rev. B: Solid State, Phys. Rev. C, and Phys. Rev. D
This paper describes an experimental determination of the polarization of low-energy cosmic-ray mu mesons at sea level. A brass plate was placed in a horizontal position inside a magnetic solenoid. Particles which arrived from directions near the vertical and stopped in the plate were detected by a coincidence-anticoincidence counter telescope. Stopped negative mu mesons were dcstroyed by nuclear capturc. Stopped positive mu mesons decayed into electrons which were detected by delayed coincidence counters placed above and below the plate. The upward and downward fluxes of the decay electrons leaving the absorber were measured alternately with and without a depolarizing magnetic field. The results of the measurements demonstrate that (1) cosmic-ray mu mesons are polarized, (2) the ratio between the downward fluxes of electrons from the decay of mu mesons stopped in a brass platc with and without a depolarizing magnetic field is 1.052 plus or minus 0.016, and (3) the indicated polarization of stopped positive mu mesons is 0.19 plus or minus 0.06 if the data are interpreted aecording to the two-component neutrino theory of mu -meson dceay. The results are consistent with theoretical predictions based on the production spectrum of pi mesons as found in other experiments. (auth)
Research Organization:
Massachusetts Inst. of Tech., Cambridge
NSA Number:
NSA-12-004878
OSTI ID:
4340782
Journal Information:
Physical Review (U.S.) Superseded in part by Phys. Rev. A, Phys. Rev. B: Solid State, Phys. Rev. C, and Phys. Rev. D, Journal Name: Physical Review (U.S.) Superseded in part by Phys. Rev. A, Phys. Rev. B: Solid State, Phys. Rev. C, and Phys. Rev. D Vol. Vol: 108; ISSN PHRVA
Country of Publication:
Country unknown/Code not available
Language:
English