DECAY-PLANE ASYMMETRY IN ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit e}^{+}}{{\mathit e}^{-}}$ DECAYS

This is the $\mathit CP$-violating asymmetry
$\mathit A$= ${\mathit N_{{\mathrm {sin\phi }}{\mathrm {cos \phi }}>0.0}−\mathit N_{{\mathrm {sin\phi }}{\mathrm {cos \phi }}<0.0}\over \mathit N_{{\mathrm {sin\phi }}{\mathrm {cos \phi }}>0.0}+\mathit N_{{\mathrm {sin\phi }}{\mathrm {cos \phi }}<0.0}}$
where $\phi $ is the angle between the ${{\mathit e}^{+}}{{\mathit e}^{-}}$ and ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$ planes in the ${{\mathit K}_L^0}$ rest frame.

$\mathit CP$ ASYMMETRY $\mathit A$ in ${{\mathit K}_L^0}$ $\rightarrow$ ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit e}^{+}}{{\mathit e}^{-}}$

INSPIRE   PDGID:
S013DPA
VALUE (%) DOCUMENT ID TECN
$\bf{ 13.7 \pm1.5 }$ OUR AVERAGE
$13.6$ $\pm1.4$ $\pm1.5$
ABOUZAID
2006
KTEV
$14.2$ $\pm3.0$ $\pm1.9$
LAI
2003C
 NA48
$13.6$ $\pm2.5$ $\pm1.2$
ALAVI-HARATI
2000B
 KTEV
Conservation Laws:
$\mathit CP$ VIOLATION OBSERVED
References:
ABOUZAID 2006
PRL 96 101801 Measurement of the ${{\mathit K}^{0}}$ Charge Radius and a $\mathit CP$-Violating Asymmetry and a Search for $\mathit CP$-Violating $\mathit E$1 Direct Photon Emission in the Rare Decay ${{\mathit K}_L^0}$ $\rightarrow$ ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit e}^{+}}{{\mathit e}^{-}}$
LAI 2003C
EPJ C30 33 Investigation of ${{\mathit K}_{{L,S}}}$ $\rightarrow$ ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit e}^{+}}{{\mathit e}^{-}}$ Decays
ALAVI-HARATI 2000B
PRL 84 408 Observation of $\mathit CP$ Violation in ${{\mathit K}_L^0}$ $\rightarrow$ ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit e}^{+}}{{\mathit e}^{-}}$ Decays