pdgLive Home   >   Meson Summary Table   >   ${{\mathit K}_S^0}$   >   ${{\mathit A}_{{S}}}$ = [ $\Gamma\mathrm {( {{\mathit K}_S^0} \rightarrow {{\mathit \pi}^{-}} {{\mathit e}^{+}} {{\mathit \nu}_{{e}}} )} - \Gamma\mathrm {( {{\mathit K}_S^0} \rightarrow {{\mathit \pi}^{+}} {{\mathit e}^{-}} {{\overline{\mathit \nu}}_{{e}}} )}$ ] $/$ SUM

${{\mathit A}_{{S}}}$ = [ $\Gamma\mathrm {( {{\mathit K}_S^0} \rightarrow {{\mathit \pi}^{-}} {{\mathit e}^{+}} {{\mathit \nu}_{{e}}} )} - \Gamma\mathrm {( {{\mathit K}_S^0} \rightarrow {{\mathit \pi}^{+}} {{\mathit e}^{-}} {{\overline{\mathit \nu}}_{{e}}} )}$ ] $/$ SUM

INSPIRE   PDGID:

S012AS

Such asymmetry violates $\mathit CP$. If $\mathit CPT$ is assumed then ${{\mathit A}_{{S}}}$ = 2 Re($\epsilon $).

VALUE ($ 10^{-3} $) EVTS DOCUMENT ID TECN $-3.8$ $\pm5.0$ $\pm2.6$ 83k 1 ANASTASI 2018 A KLOE • • We do not use the following data for averages, fits, limits, etc. • • $1.5$ $\pm9.6$ $\pm2.9$ 13k AMBROSINO 2006 E KLOE 1  ANASTASI 2018A result is a combination of the new measurement and AMBROSINO 2006E. The new ANASTASI 2018A measurement using data collected from $2004 - 2005$, which corresponds to an integrated luminosity of 1.63 fb${}^{-1}$ is A$_{S}=(-4.9$ $\pm5.7$ $\pm2.6$) $ \times 10^{-3}$.

Conservation Laws:

$\mathit CP$ INVARIANCE

References:

ANASTASI 2018A JHEP 1809 021 Measurement of the charge asymmetry for the $K_S \rightarrow \pi e \nu$ decay and test of CPT symmetry with the KLOE detector AMBROSINO 2006E PL B636 173 Study of the Branching Ratio and Charge Asymmetry for the Decay ${{\mathit K}_S^0}$ $\rightarrow$ ${{\mathit \pi}}{{\mathit e}}{{\mathit \nu}}$ with the KLOE Detector