CHARGE ASYMMETRY IN ${{\mathit K}_{{\ell3}}^{0}}$ DECAYS

Such asymmetry violates $\mathit CP$. It is related to Re($\epsilon $).

$\mathit A_{\mathit L}$ = weighted average of $\mathit A_{\mathit L}({{\mathit \mu}}$) and $\mathit A_{\mathit L}({{\mathit e}}$)

INSPIRE   PDGID:
S013AL
In previous editions and in the literature the symbol used for this asymmetry was $\delta _{L}$ or $\delta $. We use ${{\mathit A}_{{L}}}$ for consistency with ${{\mathit B}^{0}}$ asymmetry notation and with recent ${{\mathit K}_S^0}$ notation.
VALUE (%) EVTS DOCUMENT ID TECN  COMMENT
$\bf{ 0.332 \pm0.006 }$ OUR AVERAGE includes data from $\mathit A_{\mathit L}({{\mathit \mu}}$) = [$\Gamma\mathrm {({{\mathit \pi}^{-}} {{\mathit \mu}^{+}} {{\mathit \nu}_{{\mu}}} )}$ $−$ $\Gamma\mathrm {({{\mathit \pi}^{+}} {{\mathit \mu}^{-}} {{\overline{\mathit \nu}}_{{\mu}}} )}$]/SUM, $\mathit A_{\mathit L}({{\mathit e}}$) = [$\Gamma\mathrm {({{\mathit \pi}^{-}} {{\mathit e}^{+}} {{\mathit \nu}_{{e}}} )}$ $−$ $\Gamma\mathrm {({{\mathit \pi}^{+}} {{\mathit e}^{-}} {{\overline{\mathit \nu}}_{{e}}} )}$]/SUM
$0.333$ $\pm0.050$ 33M
WILLIAMS
1973
ASPK ${{\mathit K}_{{\mu3}}}{+}$ ${{\mathit K}_{{e3}}}$
Conservation Laws:
$\mathit CP$ VIOLATION OBSERVED
References:
WILLIAMS 1973
PRL 31 1521 A Measurement of the Lepton Charge Asymmetry in ${{\mathit K}_L^0}$ $\rightarrow$ ${{\mathit \pi}^{\pm}}{{\mathit \ell}^{\mp}}{{\mathit \nu}}$ Decays