A new method for measurement of the Michel parameters that describe the daughter muon polarization in the $\tau^- \to \mu^- \bar{\nu}_\mu\nu_\tau$ decay

D. Bodrov; P. Pakhlov

doi:10.1007/jhep10(2022)035

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arXiv · 2203.12743

A new method for measurement of the Michel parameters that describe the daughter muon polarization in the $\tau^- \to \mu^- \bar{\nu}_\mu\nu_\tau$ decay

D. Bodrov·P. Pakhlov

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Abstract

This paper provides a detailed description of the method for the first direct measurement of all Michel parameters in the $\tau^- \to \mu^- \bar{\nu}_\mu\nu_\tau$ decay related to the polarization of the daughter muon. An application of the suggested method in the existing and future experiments at $e^+e^-$ colliders is considered. We have performed a feasibility study for the future Super Charm-Tau Factory and Belle II experiments. For the first one, the sensitivity to the Michel parameters $\xi'$, $\xi''$, $\eta''$, $\alpha'/A$, and $\beta'/A$ is estimated. For the latter, only one Michel parameter, $\xi'$, for which the sensitivity is maximum, is considered.

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D. Bodrov, P. Pakhlov. 2022-03-23. A new method for measurement of the Michel parameters that describe the daughter muon polarization in the $\tau^- \to \mu^- \bar{\nu}_\mu\nu_\tau$ decay. https://doi.org/10.1007/jhep10(2022)035

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