${{\boldsymbol \mu}}$ DECAY PARAMETERS

$\xi {{}^\prime}$ = LONGITUDINAL POLARIZATION OF ${{\boldsymbol e}^{+}}$ INSPIRE search

($\mathit V−\mathit A$) theory predicts the longitudinal polarization = $\pm1$ for ${{\mathit e}^{\pm}}$, respectively. We have flipped the sign for ${{\mathit e}^{-}}$ so our programs can average.

VALUE

EVTS

DOCUMENT ID

TECN

CHG

COMMENT

$\bf{ 1.00 \pm0.04}$

OUR AVERAGE

$0.998$ $\pm0.045$

BURKARD

1985

CNTR

Bhabha + annihil

$0.89$ $\pm0.28$

29k

SCHWARTZ

1967

OSPK

Moller scattering

$0.94$ $\pm0.38$

BLOOM

1964

CNTR

Brems. transmiss.

$1.04$ $\pm0.18$

DUCLOS

1964

CNTR

Bhabha scattering

$1.05$ $\pm0.30$

BUHLER

1963

CNTR

Annihilation

References:

BURKARD

1985

PL 150B 242

Muon Decay: Measurement of the Positron Polarization and Implications for the Spectrum Shape Parameter ${{\mathit \eta}}$, $\mathit V-A$ and $\mathit T$ Invariance

SCHWARTZ

1967

PR 162 1306

Helicity of Electrons from ${{\mathit \mu}^{-}}$ Decay

BLOOM

1964

PL 8 87

Measurement, by Bremsstrahlung Transmission, of the Polarization of ${{\mathit e}^{+}}$ from ${{\mathit \mu}^{+}}$ $\rightarrow$ ${{\mathit e}^{+}}{{\mathit \nu}_{{e}}}{{\overline{\mathit \nu}}_{{\mu}}}$

DUCLOS

1964

PL 9 62

Measurement of the ${{\mathit e}^{+}}$ Polarization in Muon Decay by Means of Bhabha Scattering

BUHLER

1963

PL 7 368

A Measurement of the ${{\mathit e}^{+}}$ Polarization in Muon Decay: the ${{\mathit e}^{+}}$ Annihilation Method