Observation of $τ^ − → π^ − ν_ τ e^ + e^ −$ and search for $τ ^− → π^ − ν_ τ μ ^+ μ^ −$
| Popis: | We present the first measurements of branching fractions of rare tau-lepton decays, τ-→π-ντℓ+ℓ- (ℓ=e or μ), 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 τ-→π-ντe+e- decay is observed for the first time with 7.0σ significance. The partial branching fraction determined by the structure-dependent mechanisms mediated by either a vector or an axial-vector current for the mass region Mπee>1.05 GeV/c2 is measured to be B(τ-→π-ντe+e-)[Mπ-e+e->1.05 GeV/c2]=(5.90±0.53±0.85±0.11)×10-6, where the first uncertainty is statistical, the second is systematic, and the third is due to model dependence. In the full phase space, due to the different detection efficiencies for the structure-dependent mechanisms mediated by axial-vector and vector currents, the branching fraction varies from BA(τ-→π-ντe+e-)=(1.46±0.13±0.21)×10-5 to BV(τ-→π-ντe+e-)=(3.01±0.27±0.43)×10-5, respectively. An upper limit is set on the branching fraction of the τ-→π-ντμ+μ- decay, B(τ-→π-ντμ+μ-) |
|---|---|
| Jazyk: | English |
| DOI: | 10.1103/PhysRevD.100.071101 |
| Přístupová URL adresa: | https://explore.openaire.eu/search/publication?articleId=od______1108::2a0aa3e345130f5843ea018d3733d64a https://bib-pubdb1.desy.de/record/428365 |
| Rights: | OPEN |
| Přírůstkové číslo: | edsair.od......1108..2a0aa3e345130f5843ea018d3733d64a |
| Autor: | Jin, Yifan, Aihara, H., Badhrees, I., Liptak, Z., Liventsev, D., Lu, P.-C., Luo, T., MacNaughton, J., Masuda, M., Matsuda, T., Matvienko, D., Merola, M., Miyabayashi, K., Bahinipati, S., Miyata, H., Mizuk, R., Mori, T., Mussa, R., Nakano, E., Nakao, M., Nath, K. J., Natkaniec, Z., Nayak, M., Niiyama, M., Bansal, V., Nisar, N. K., Nishida, S., Ogawa, S., Ono, H., Onuki, Y., Pakhlov, P., Pakhlova, G., Pal, B., Pardi, S., Park, H., Behera, P., Park, S.-H., Patra, S., Paul, S., Pedlar, T. K., Pestotnik, R., Piilonen, L. E., Popov, V., Prencipe, E., Purohit, M. V., Rostomyan, A., Berger, M., Russo, G., Sahoo, D., Sakai, Y., Salehi, M., Sandilya, S., Santelj, L., Sanuki, T., Savinov, V., Schneider, O., Schnell, G., Bhardwaj, V., Schueler, J., Schwanda, C., Seino, Y., Senyo, K., Seon, O., Sevior, M. E., Shebalin, V., Shen, C. P., Shiu, J.-G., Shwartz, B., Bilka, T., Simon, F., Singh, J. B., Sokolov, A., Solovieva, E., Stanič, S., Starič, M., Stottler, Z. S., Strube, J. F., Sumiyoshi, T., Takizawa, M., Biswal, J., Tamponi, U., Tanida, K., Tenchini, F., Trabelsi, K., Uchida, M., Uglov, T., Unno, Y., Uno, S., Urquijo, P., Usov, Y., Bobrov, A., Van Tonder, R., Varner, G., Vinokurova, A., Vorobyev, V., Vossen, A., Wang, B., Wang, C. H., Wang, M.-Z., Wang, P., Watanuki, S., Bonvicini, G., Won, E., Yang, S. B., Ye, H., Yin, J. H., Yuan, C. Z., Yusa, Y., Zhang, Z. P., Zhilich, V., Zhukova, V., Belle Collaboration, Epifanov, D., Bozek, A., Bračko, M., Campajola, M., Cao, L., Červenkov, D., Chekelian, V., Chen, A., Cheon, B. G., Chilikin, K., Cho, H. E., Adachi, I., Cho, K., Choi, Y., Choudhury, S., Cinabro, D., Cunliffe, S., Di Carlo, S., Doležal, Z., Dong, T. V., Dossett, D., Eidelman, S., Al Said, S., Fast, J. E., Ferber, T., Fulsom, B. G., Garg, R., Gaur, V., Gabyshev, N., Garmash, A., Giri, A., Goldenzweig, P., Golob, B., Asner, D. M., Greenwald, D., Grzymkowska, O., Haba, J., Hayasaka, K., Hayashii, H., Hedges, M. T., Hou, W.-S., Huang, K., Iijima, T., Inami, K., Aulchenko, V., Inguglia, G., Ishikawa, A., Iwasaki, M., Iwasaki, Y., Jacobs, W. W., Jeon, H. B., Jia, S., Joffe, D., Joo, K. K., Kahn, J., Aushev, T., Kaliyar, A. B., Karyan, G., Kawasaki, T., Kichimi, H., Kiesling, C., Kim, D. Y., Kim, H. J., Kim, K. T., Kim, S. H., Kinoshita, K., Ayad, R., Kodyš, P., Korpar, S., Kotchetkov, D., Križan, P., Kroeger, R., Krokovny, P., Kulasiri, R., Kumar, R., Kuzmin, A., Kwon, Y.-J., Babu, V., Lalwani, K., Lange, J. S., Lee, J. Y., Lee, S. C., Li, C. H., Li, L. K., Li, Y. B., Li Gioi, L., Libby, J., Lieret, K. |
| Jazyk: | angličtina |
| Rok vydání: | 2019 |
| Předmět: |
rare decay [tau]
branching ratio: measured [tau] (pi electron positron) [mass spectrum] BELLE tau- --> pi- neutrino/tau electron positron annihilation [electron positron] semileptonic decay [tau] tau- --> pi- neutrino/tau muon+ muon phase space KEK-B axial-vector [current] efficiency colliding beams [electron positron] ddc:530 mediation pair production [electron] pair production [muon] branching ratio: upper limit [tau] statistical experimental results |
| Zdroj: | Physical review / D 100(7), 071101 (2019). doi:10.1103/PhysRevD.100.071101 |
| DOI: | 10.1103/PhysRevD.100.071101 |
| Popis: | We present the first measurements of branching fractions of rare tau-lepton decays, τ-→π-ντℓ+ℓ- (ℓ=e or μ), 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 τ-→π-ντe+e- decay is observed for the first time with 7.0σ significance. The partial branching fraction determined by the structure-dependent mechanisms mediated by either a vector or an axial-vector current for the mass region Mπee>1.05 GeV/c2 is measured to be B(τ-→π-ντe+e-)[Mπ-e+e->1.05 GeV/c2]=(5.90±0.53±0.85±0.11)×10-6, where the first uncertainty is statistical, the second is systematic, and the third is due to model dependence. In the full phase space, due to the different detection efficiencies for the structure-dependent mechanisms mediated by axial-vector and vector currents, the branching fraction varies from BA(τ-→π-ντe+e-)=(1.46±0.13±0.21)×10-5 to BV(τ-→π-ντe+e-)=(3.01±0.27±0.43)×10-5, respectively. An upper limit is set on the branching fraction of the τ-→π-ντμ+μ- decay, B(τ-→π-ντμ+μ-) |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|