First measurement of the Michel parameter ${\xi }^{\prime }$ in the ${\tau }^{-}\to {\mu }^{-}{\bar{\nu }}_{\mu }{\nu }_{\tau }$ decay at Belle

Belle Collaboration, D. Bodrov, P. Pakhlov +191

We report the first measurement of the Michel parameter ${\xi }^{\prime }$ in the ${\tau }^{-}\to {\mu }^{-}{\bar{\nu }}_{\mu }{\nu }_{\tau }$ decay with a new method proposed just recently. The measurement is based on the reco…