$CP$ violation in ${\eta }^{(\prime )}\to {\pi }^{+}{\pi }^{-}{\mu }^{+}{\mu }^{-}$ decays

Maximilian Zillinger, Bastian Kubis, Pablo Sánchez-Puertas

It has been pointed out recently that a certain set of dimension-6 scalar $P$- and $CP$-violating light-quark-muon operators may be tested in $\eta$ and ${\eta }^{\prime }$ decays to various final s…