pdgLive Home   >   Meson Summary Table   >   ${{\mathit K}^{\pm}}$   >   A$_{FB}({{\mathit K}}{}^{\pm{}}_{{{\mathit \pi}} {{\mathit \mu}} {{\mathit \mu}} }$) = ${\Gamma\mathrm {(cos({{\mathit \theta}}_{ {{\mathit K}} {{\mathit \mu}} })>0)}−\Gamma\mathrm {(cos({{\mathit \theta}}_{ {{\mathit K}} {{\mathit \mu}} })<0)}\over \Gamma\mathrm {(cos({{\mathit \theta}}_{ {{\mathit K}} {{\mathit \mu}} })>0)}+\Gamma\mathrm {(cos({{\mathit \theta}}_{ {{\mathit K}} {{\mathit \mu}} })<0)}}$

FORWARD-BACKWARD ASYMMETRY IN ${{\mathit K}^{\pm}}$ DECAYS

A$_{FB}({{\mathit K}}{}^{\pm{}}_{{{\mathit \pi}} {{\mathit \mu}} {{\mathit \mu}} }$) = ${\Gamma\mathrm {(cos({{\mathit \theta}}_{ {{\mathit K}} {{\mathit \mu}} })>0)}−\Gamma\mathrm {(cos({{\mathit \theta}}_{ {{\mathit K}} {{\mathit \mu}} })<0)}\over \Gamma\mathrm {(cos({{\mathit \theta}}_{ {{\mathit K}} {{\mathit \mu}} })>0)}+\Gamma\mathrm {(cos({{\mathit \theta}}_{ {{\mathit K}} {{\mathit \mu}} })<0)}}$

INSPIRE   PDGID:

S010AFB

VALUE CL% DOCUMENT ID TECN  COMMENT $\bf{<0.009}$ 90 1 CORTINA-GIL 2022 A NA62 $2017 - 18$ data • • We do not use the following data for averages, fits, limits, etc. • • $<0.023$ 90 2 BATLEY 2011 A NA48 1  CORTINA-GIL 2022A measured the asymmetry A$_{FB}$ = $0.000$ $\pm0.007$. The quoted 90$\%$ C.L. was obtained via private communication and also presented at the Moriond 2023 conference. The authors will publish this limit in an addendum to the publication. 2  BATLEY 2011A gives a corresponding value of the asymmetry A$_{FB}$ = $-0.024$ $\pm0.018$.

References:

CORTINA-GIL 2022A JHEP 2211 011 A measurement of the $K^{+} \to \pi^{+} \mu^{+} \mu^{-}$ decay BATLEY 2011A PL B697 107 New Measurement of the ${{\mathit K}^{\pm}}$ $\rightarrow$ ${{\mathit \pi}^{\pm}}{{\mathit \mu}^{+}}{{\mathit \mu}^{-}}$ Decay

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