Journal article

Observation of tau(-) -> pi(-)nu(tau)e( )e(-) and search for tau(-) -> pi(-)nu(tau)mu( )mu(-)

Y Jin, H Aihara, D Epifanov, I Adachi, S Al Said, DM Asner, V Aulchenko, T Aushev, R Ayad, V Babu, I Badhrees, S Bahinipati, V Bansal, P Behera, M Berger, V Bhardwaj, T Bilka, J Biswal, A Bobrov, G Bonvicini Show all

PHYSICAL REVIEW D | AMER PHYSICAL SOC | Published : 2019

Abstract

We present the first measurements of branching fractions of rare tau-lepton decays, τ-→π-ντ+- (=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..

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Grants

Awarded by Australian Research Council


Awarded by National Natural Science Foundation of China


Awarded by Key Research Program of Frontier Sciences, Chinese Academy of Sciences (CAS)


Awarded by Shanghai Pujiang Program


Awarded by Ministry of Education, Youth and Sports of the Czech Republic


Awarded by National Research Foundation (NRF) of Korea


Awarded by Russian Federation Government


Funding Acknowledgements

The authors thank Pablo G. Roig and Gabriel L. Castro from CINVESTAV for the extensive help and fruitful discussions. We thank the KEKB group for the excellent operation of the accelerator; the KEK cryogenics group for the efficient operation of the solenoid; the KEK computer group, and the Pacific Northwest National Laboratory (PNNL) Environmental Molecular Sciences Laboratory (EMSL) computing group for strong computing support; and the National Institute of Informatics, and Science Information NETwork 5 (SINET5) for valuable network support. We acknowledge support from the Ministry of Education, Culture, Sports, Science, and Technology (MEXT) of Japan, the Japan Society for the Promotion of Science (JSPS), and the Tau-Lepton Physics Research Center of Nagoya University; the Australian Research Council including Grants No. DP180102629, No. DP170102389, No. DP170102204, No. DP150103061, and No. FT130100303; Austrian Science Fund (FWF); the National Natural Science Foundation of China under Contracts No. 11435013, No. 11475187, No. 11521505, No. 11575017, No. 11675166, and No. 11705209; Key Research Program of Frontier Sciences, Chinese Academy of Sciences (CAS), Grant No. QYZDJ-SSW-SLH011; the CAS Center for Excellence in Particle Physics (CCEPP); the Shanghai Pujiang Program under Grant No. 18PJ1401000; the Ministry of Education, Youth and Sports of the Czech Republic under Contract No. LTT17020; the Carl Zeiss Foundation, the Deutsche Forschungsgemeinschaft, the Excellence Cluster Universe, and the VolkswagenStiftung; the Department of Science and Technology of India; the Istituto Nazionale di Fisica Nucleare of Italy; National Research Foundation (NRF) of Korea Grants No. 2015H1A2A1033649, No. 2016R1D1A1B01010135, No. 2016K1A3A7A09005 603, No. 2016R1D1A1B02012900, No. 2018R1A2B3003 643, No. 2018R1A6A1A06024970, and No. 2018R1D1 A1B07047294; Radiation Science Research Institute, Foreign Large-size Research Facility Application Supporting project, the Global Science Experimental Data Hub Center of theKorea Institute of Science and Technology Information and KREONET/GLORIAD; the Polish Ministry of Science and Higher Education and the National Science Center; the Grant of the Russian Federation Government, Grant No. 14.W03.31.0026; the Slovenian Research Agency; Ikerbasque, Basque Foundation for Science, Spain; the Swiss National Science Foundation; the Ministry of Education and the Ministry of Science and Technology of Taiwan; and the United States Department of Energy and the National Science Foundation.