Measurement of the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>τ</mml:mi></mml:math>-lepton mass with the Belle II experiment

We present a measurement of the $\ensuremath{\tau}$-lepton mass using a sample of about 175 million ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}{\ensuremath{\tau}}^{+}{\ensuremath{\tau}}^{\ensuremath{-}}$ events collected with the Belle II detector at the SuperKEKB ${e}^{+}{e}^{\ensuremath{-}}$ collider at a center-of-mass energy of 10.579 GeV. This sample corresponds to an integrated luminosity of $190\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$. We use the kinematic edge of the $\ensuremath{\tau}$ pseudomass distribution in the decay ${\ensuremath{\tau}}^{\ensuremath{-}}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\nu}}_{\ensuremath{\tau}}$ and measure the $\ensuremath{\tau}$ mass to be $1777.09\ifmmode\pm\else\textpm\fi{}0.08\ifmmode\pm\else\textpm\fi{}0.11\text{ }\text{ }\mathrm{MeV}/{c}^{2}$, where the first uncertainty is statistical and the second systematic. This result is the most precise to date.

Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.