Search for $\mathit{CP}$ Violation in $\tau \to \mathit{K}\pi {\nu }_{\tau }$ Decays

We search and find no evidence for $\mathrm{CP}$ violation in $\tau$ decays into the $K\pi {\nu }_{\tau }$ final state. We provide limits on the imaginary part of the coupling constant $\Lambda$ describing a relative contribution of the $\mathrm{CP}$ violating processes with respect to the standard model to be $-0.172<\mathrm{Im}\left(\Lambda \right)<0.067\mathrm{}$ at $90\%$ C.L.