{"paper":{"title":"Observation of $ \\tau^- \\rightarrow \\pi^- \\nu_{\\tau} e^+ e^-$ and search for $\\tau^- \\rightarrow \\pi^- \\nu_{\\tau} \\mu^+ \\mu^-$","license":"http://creativecommons.org/licenses/by/4.0/","headline":"","cross_cats":[],"primary_cat":"hep-ex","authors_text":"A. B. Kaliyar, A. Bobrov, A. Bozek, A. Chen, A. Giri, A. Ishikawa, A. Kuzmin, A. Rostomyan, A. Sokolov, A. Vinokurova, A. Vossen, Belle Collaboration: Y. Jin, B. G. Cheon, B. G. Fulsom, B. Golob, B. Pal, B. Shwartz, B. Wang, C. H. Li, C. H. Wang, C. Kiesling, C. P. Shen, C. Schwanda, C. Z. Yuan, D. Cinabro, D. Dossett, D. Epifanov, D. Greenwald, D. Joffe, D. Kotchetkov, D. Liventsev, D. M. Asner, D. Matvienko, D. Sahoo, D. \\v{C}ervenkov, D. Y. Kim, E. Nakano, E. Prencipe, E. Solovieva, E. Won, F. Simon, F. Tenchini, G. Bonvicini, G. Inguglia, G. Karyan, G. Pakhlova, G. Russo, G. Schnell, G. Varner, H. Aihara, H. B. Jeon, H. E. Cho, H. Hayashii, H. J. Kim, H. Kichimi, H. Miyata, H. Ono, H. Park, H. Ye, I. Adachi, I. Badhrees, J. Biswal, J. B. Singh, J. E. Fast, J. F. Strube, J.-G. Shiu, J. Haba, J. H. Yin, J. Kahn, J. Libby, J. MacNaughton, J. Schueler, J. S. Lange, J. Y. Lee, K. Chilikin, K. Cho, K. Hayasaka, K. Huang, K. Inami, K. J. Nath, K. Kinoshita, K. K. Joo, K. Lalwani, K. Lieret, K. Miyabayashi, K. Senyo, K. Tanida, K. T. Kim, K. Trabelsi, L. Cao, L. E. Piilonen, L. K. Li, L. Li Gioi, L. Santelj, M. Berger, M. Bra\\v{c}ko, M. Campajola, M. E. Sevior, M. Iwasaki, M. Masuda, M. Merola, M. Nakao, M. Nayak, M. Niiyama, M. Salehi, M. Stari\\v{c}, M. Takizawa, M. T. Hedges, M. Uchida, M.-Z. Wang, N. Gabyshev, N. K. Nisar, O. Grzymkowska, O. Schneider, O. Seon, P. Behera, P.-C. Lu, P. Goldenzweig, P. Kody\\v{s}, P. Kri\\v{z}an, P. Krokovny, P. Pakhlov, P. Urquijo, P. Wang, R. Ayad, R. Garg, R. Kroeger, R. Kulasiri, R. Kumar, R. Mizuk, R. Mussa, R. Pestotnik, R. van Tonder, S. Al Said, S. Bahinipati, S. B. Yang, S. Choudhury, S. C. Lee, S. Cunliffe, S. Di Carlo, S. Eidelman, S. H. Kim, S.-H. Park, S. Jia, S. Korpar, S. Nishida, S. Ogawa, S. Pardi, S. Patra, S. Paul, S. Sandilya, S. Stani\\v{c}, S. Uno, S. Watanuki, T. Aushev, T. Bilka, T. Ferber, T. Iijima, T. Kawasaki, T. K. Pedlar, T. Luo, T. Matsuda, T. Mori, T. Sanuki, T. Sumiyoshi, T. Uglov, T. V. Dong, U. Tamponi, V. Aulchenko, V. Babu, V. Bansal, V. Bhardwaj, V. Chekelian, V. Gaur, V. Popov, V. Savinov, V. Shebalin, V. Vorobyev, V. Zhilich, V. Zhukova, W.-S. Hou, W. W. Jacobs, Y. B. Li, Y. Choi, Y. Iwasaki, Y.-J. Kwon, Y. Onuki, Y. Sakai, Y. Seino, Y. Unno, Y. Usov, Y. Yusa, Z. Dole\\v{z}al, Z. Liptak, Z. Natkaniec, Z. P. Zhang, Z. S. Stottler","submitted_at":"2019-08-25T16:09:32Z","abstract_excerpt":"We present the first measurements of branching fractions of rare tau-lepton decays, $\\tau^- \\rightarrow \\pi^- \\nu_{\\tau} \\ell^+ \\ell^-$ ($\\ell = e$ or $\\mu$), using a data sample corresponding to 562 fb$^{-1}$ collected at a center-of-mass energy of 10.58 GeV with the Belle detector at the KEKB asymmetric-energy $e^+ e^-$ collider. The $\\tau^- \\rightarrow \\pi^- \\nu_\\tau e^+ e^-$ decay is observed for the first time with 7.0$\\sigma$ significance. The partial branching fraction determined by the structure-dependent mechanisms mediated by either a vector or an axial-vector current for the mass re"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1908.09353","kind":"arxiv","version":3},"verdict":{"id":null,"model_set":{},"created_at":null,"strongest_claim":"","one_line_summary":"","pipeline_version":null,"weakest_assumption":"","pith_extraction_headline":""},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/1908.09353/integrity.json","findings":[],"available":true,"detectors_run":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938"},"references":{"count":0,"sample":[],"resolved_work":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","internal_anchors":0},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}