Towards a determination of the tau lepton dipole moments

Abstract

The τ anomalous magnetic moment $a_{\tau }$ and electric dipole moment $d_{\tau }$ have not yet been observed. The present bounds on their values are of order ${10}^{-2}$ and ${10}^{-17}e\text{cm}$, respectively. We propose to measure $a_{\tau }$ with a precision of $O\left({10}^{-3}\right)$ or better and improve the existing limits on $d_{\tau }$ using precise ${\tau }^{-}\to l^{-}{\nu }_{\tau }{\overline{\nu }}_l\gamma$ ($l=e$ or μ) data from high-luminosity B factories. A detailed feasibility study of this method is underway.