# $\xi {{}^\prime}{{}^\prime}$ PARAMETER INSPIRE search

VALUE EVTS DOCUMENT ID TECN CHG  COMMENT
$\bf{ 0.98 \pm0.04}$ OUR AVERAGE
$0.981$ $\pm0.045$ $\pm0.003$ 3.87M
 2014
CNTR + Bhabha + annihil
$0.65$ $\pm0.36$ 326k 1
 1985
CNTR + Bhabha + annihil
1  BURKARD 1985 measure ($\xi {{}^\prime}{{}^\prime}-\xi {}\xi {{}^\prime})/\xi$ and $\xi {{}^\prime}$ and set $\xi$ = 1.
References:
 PRIEELS 2014
PR D90 112003 Measurement of the Parameter ${{\mathit \xi}^{\,'}}{}^{'}$ in Polarized Muon Decay and Implications on Exotic Couplings of the Leptonic Weak Interaction
 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