# Measurement of the Lifetime of the $\tau$ Lepton

Abstract : The tau lepton lifetime is measured with the L3 detector at LEP using the complete data taken at centre-of-mass energies around the Z pole resulting in $\tau_{\tau}\,=\,293.2\,\pm\,2.0~\mbox{(stat)}\,\pm\, 1.5~\mbox{(syst)}$ fs. The comparison of this result with the muon lifetime supports lepton universality of the weak charged current at the level of six per mille. Assuming lepton universality, the value of the strong coupling constant, $\alpha_s$ is found to be $\alpha_s(m_{\tau}^2)$ = 0.319 $\pm$ 0.015~\mbox{(exp)} $\pm$ 0.014~\mbox{(theory)}.
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Journal articles

Cited literature [17 references]

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Submitted on : Monday, July 24, 2000 - 12:02:50 PM
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### Citation

M. Acciarri, P. Achard, O. Adriani, M. Aguilar-Benitez, J. Alcaraz, et al.. Measurement of the Lifetime of the $\tau$ Lepton. Physics Letters B, Elsevier, 2000, 479, pp.67-78. ⟨10.1016/S0370-2693(00)00347-6⟩. ⟨in2p3-00005340⟩

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