title: Muon decay: measurement of the transverse polarization of the decay positrons and its implications for the fermi coupling constant and time reversal invariance.
abstract: The two transverse polarization components P(T1) and P(T2) of the e(+) from the decay of polarized mu(+) have been measured as a function of the e(+) energy. Their energy averaged values are P(T1)=(6.3+/-7.7+/-3.4) x 10(-3) and P(T2)=(-3.7+/-7.7+/-3.4) x 10(-3). From the energy dependence of P(T1) and P(T2) the decay parameters eta,eta('') and alpha(')/A,beta(')/A are derived, respectively. Assuming only one additional coupling besides the dominant V-A interaction one gets improved limits on eta, beta(')/A, and the scalar coupling constant g(S)(RR): eta=(-2.1+/-7.0+/-1.0) x 10(-3), beta(')/A=(-1.3+/-3.5+/-0.6) x 10(-3), Re{g(S)(RR)}=(-4.2+/-14.0+/-2.0) x 10(-3), and Im{g(S)(RR)}=(5.2+/-14.0+/-2.4) x 10(-3).
authors.affiliation: Institute for Particle Physics (IPP), ETH Zürich, 8093 Zürich, Switzerland.
authors.forename: N
authors.initials: N
authors.lastname: Danneberg
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authors.lastname: Fetscher
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authors.lastname: Köhler
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authors.lastname: Lang
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authors.lastname: Schweizer
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authors.lastname: von Allmen
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authors.lastname: Bodek
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authors.lastname: Jarczyk
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authors.lastname: Kirch
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authors.lastname: Kozela
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authors.initials: E
authors.lastname: Stephan