# Measurements of the $\tau$ Mass and Mass Difference of the $\tau^{+}$ and $\tau^{-}$} at BaBar

Abstract : We present the result from a precision measurement of the mass of the $\tau$ lepton, $M_\tau$, based on $423 fb^{-1}$ of data recorded at the $\Upsilon(4S)$ resonance with the BaBar detector. Using a pseudomass endpoint method, we determine the mass to be $1776.68 \pm 0.12 (stat) \pm 0.41 (syst) MeV$. We also measure the mass difference between the $\tau^+$ and $\tau^-$, and obtain $(M_{\tau^{+}}-M_{\tau^{-}})/M^\tau_{AVG} = (-3.4 \pm 1.3 (stat) \pm 0.3 (syst)) \times 10^{-4}$, where $M^\tau_{AVG}$ is the average value of $M_{\tau^+}$ and $M_{\tau^-}$.
Document type :
Journal articles

http://hal.in2p3.fr/in2p3-00420591
Contributor : Claudine Bombar <>
Submitted on : Tuesday, September 29, 2009 - 1:50:59 PM
Last modification on : Saturday, November 28, 2020 - 12:58:03 PM

### Citation

B. Aubert, Y. Karyotakis, J.P. Lees, V. Poireau, E. Prencipe, et al.. Measurements of the $\tau$ Mass and Mass Difference of the $\tau^{+}$ and $\tau^{-}$} at BaBar. Physical Review D, American Physical Society, 2009, 80, pp.092005. ⟨10.1103/PhysRevD.80.092005⟩. ⟨in2p3-00420591⟩

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