Track reconstruction efficiency measurement using $e^{+}e^{-}\rightarrow\tau^+\tau^-$ events at Belle II
Résumé
We present the Belle II track reconstruction efficiency and Monte Carlo efficiency correction factors using $\tau$-pair events, in which one $\tau$ lepton decays leptonically ($\tau \rightarrow l \nu\nu$, $l = e, \mu$) while the other decays hadronically into three charged pions ($\tau \rightarrow 3\pi\nu + n\pi^{0}$). These measurements are performed using the $e^{+}e^{-}$ collision data recorded during the 2019 data taking periods, corresponding to a total integrated lumnosity of $8.8$~fb$^{-1}$.