# $({\boldsymbol \tau}_{{{\boldsymbol \pi}^{+}}}–{\boldsymbol \tau}_{{{\boldsymbol \pi}^{-}}})/{\boldsymbol \tau}_{\mathrm {average}}$ INSPIRE search

A test of $\mathit CPT$ invariance.
VALUE ($10^{-4}$) DOCUMENT ID TECN
$5.5$ $\pm7.1$
 1971
CNTR
• • • We do not use the following data for averages, fits, limits, etc. • • •
$-14$ $\pm29$
 1968
CNTR
$40$ $\pm70$
 1966
CNTR
$23$ $\pm40$ 1
 1966
CNTR
1  This is the most conservative value given by LOBKOWICZ 1966 .
Conservation Laws:
 $\mathit CPT$ INVARIANCE
References:
 AYRES 1971
PR D3 1051 Measurements of the Lifetimes of Positive and Negative Pions
 PETRUKHIN 1968
JINR P1 3862 Comparison of the Life-Times of the Charged Pions
 BARDON 1966
PRL 16 775 Comparison of Pion and Antipion Lifetimes
 LOBKOWICZ 1966
PRL 17 548 Precise Measurement of the ${{\mathit K}^{+}}/{{\mathit K}^{-}}$ and ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$ Lifetime Ratios