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arXiv · 1310.8503

Measurement of the $τ$-lepton lifetime at Belle

Belle Collaboration·K. Belous·M. Shapkin·A. Sokolov·I. Adachi·H. Aihara·D. M. Asner·V. Aulchenko·A. M. Bakich·A. Bala·B. Bhuyan·A. Bobrov·A. Bondar·G. Bonvicini·A. Bozek·M. Bračko·T. E. Browder·D. Červenkov·V. Chekelian·A. Chen·B. G. Cheon·K. Chilikin·R. Chistov·K. Cho·V. Chobanova·Y. Choi·D. Cinabro·J. Dalseno·Z. Doležal·D. Dutta·S. Eidelman·D. Epifanov·H. Farhat·J. E. Fast·T. Ferber·V. Gaur·S. Ganguly·A. Garmash·R. Gillard·Y. M. Goh·B. Golob·J. Haba·T. Hara·K. Hayasaka·H. Hayashii·Y. Hoshi·W. -S. Hou·T. Iijima·K. Inami·A. Ishikawa·R. Itoh·T. Iwashita·I. Jaegle·T. Julius·E. Kato·H. Kichimi·C. Kiesling·D. Y. Kim·H. J. Kim·J. B. Kim·M. J. Kim·Y. J. Kim·K. Kinoshita·B. R. Ko·P. Kodyš·S. Korpar·P. Križan·P. Krokovny·T. Kuhr·A. Kuzmin·Y. -J. Kwon·J. S. Lange·S. -H. Lee·J. Libby·D. Liventsev·P. Lukin·D. Matvienko·H. Miyata·R. Mizuk·G. B. Mohanty·T. Mori·R. Mussa·Y. Nagasaka·E. Nakano·M. Nakao·M. Nayak·E. Nedelkovska·C. Ng·N. K. Nisar·S. Nishida·O. Nitoh·S. Ogawa·S. Okuno·S. L. Olsen·W. Ostrowicz·G. Pakhlova·C. W. Park·H. Park·H. K. Park·T. K. Pedlar
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Abstract

The lifetime of the $τ$-lepton is measured using the process $e^+e^-\rightarrowτ^+τ^-$, where both $τ$-leptons decay to $3πν_τ$. The result for the mean lifetime, based on $711\,\mathrm{fb}^{-1}$ of data collected with the Belle detector at the $Υ(4S)$ resonance and $60\,\mathrm{MeV}$ below, is $τ= (290.17 \pm 0.53(\mathrm{stat.}) \pm 0.33(\mathrm{syst.}))\cdot10^{-15}\,\mathrm{s}$. The first measurement of the lifetime difference between $τ^+$ and $τ^-$ is performed. The upper limit on the relative lifetime difference between positive and negative $τ$-leptons is $|Δτ| / τ< 7.0 \times 10^{-3}$ at 90% CL.

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Belle Collaboration, K. Belous, M. Shapkin, A. Sokolov, I. Adachi, H. Aihara, D. M. Asner, V. Aulchenko, A. M. Bakich, A. Bala, B. Bhuyan, A. Bobrov, A. Bondar, G. Bonvicini, A. Bozek, M. Bračko, T. E. Browder, D. Červenkov, V. Chekelian, A. Chen, B. G. Cheon, K. Chilikin, R. Chistov, K. Cho, V. Chobanova, Y. Choi, D. Cinabro, J. Dalseno, Z. Doležal, D. Dutta, S. Eidelman, D. Epifanov, H. Farhat, J. E. Fast, T. Ferber, V. Gaur, S. Ganguly, A. Garmash, R. Gillard, Y. M. Goh, B. Golob, J. Haba, T. Hara, K. Hayasaka, H. Hayashii, Y. Hoshi, W. -S. Hou, T. Iijima, K. Inami, A. Ishikawa, R. Itoh, T. Iwashita, I. Jaegle, T. Julius, E. Kato, H. Kichimi, C. Kiesling, D. Y. Kim, H. J. Kim, J. B. Kim, M. J. Kim, Y. J. Kim, K. Kinoshita, B. R. Ko, P. Kodyš, S. Korpar, P. Križan, P. Krokovny, T. Kuhr, A. Kuzmin, Y. -J. Kwon, J. S. Lange, S. -H. Lee, J. Libby, D. Liventsev, P. Lukin, D. Matvienko, H. Miyata, R. Mizuk, G. B. Mohanty, T. Mori, R. Mussa, Y. Nagasaka, E. Nakano, M. Nakao, M. Nayak, E. Nedelkovska, C. Ng, N. K. Nisar, S. Nishida, O. Nitoh, S. Ogawa, S. Okuno, S. L. Olsen, W. Ostrowicz, G. Pakhlova, C. W. Park, H. Park, H. K. Park, T. K. Pedlar. 2013-10-31. Measurement of the $τ$-lepton lifetime at Belle. https://doi.org/10.1103/physrevlett.112.031801

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