\begin{document}$B_c \to \tau\nu_\tau$\end{document} branching ratio provides an advantageous opportunity for understanding the electroweak structure of the Standard Model, measuring the CKM matrix element \begin{document}$|V_{cb}|$\end{document}, and probing new physics models. In this paper, we discuss the potential of measuring the process \begin{document}$B_c \to \tau\nu_\tau$\end{document} with \begin{document}$\tau$\end{document} decaying leptonically at the proposed Circular Electron Positron Collider (CEPC). We conclude that during the Z pole operation, the channel signal can achieve five-\begin{document}$\sigma$\end{document} significance with \begin{document}$\sim 10^9$\end{document} Z decays, and the signal strength accuracies for \begin{document}$B_c \to \tau\nu_\tau$\end{document} can reach around 1% level at the nominal CEPC Z pole statistics of one trillion Z decays, assuming the total \begin{document}$B_c \to \tau \nu_\tau$\end{document} yield is \begin{document}$3.6 \times 10^6$\end{document}. Our theoretical analysis indicates the accuracy could provide a strong constraint on the general effective Hamiltonian for the \begin{document}$b \to c\tau\nu$\end{document} transition. If the total \begin{document}$B_c$\end{document} yield can be determined to \begin{document}${\cal{O}}$\end{document}(1%) level of accuracy in the future, these results also imply \begin{document}$|V_{cb}|$\end{document} could be measured up to \begin{document}${\cal{O}}$\end{document}(1%) level of accuracy."> Analysis of <i>B<sub>c</sub></i> → <i>τν<sub>τ</sub></i> at CEPC -
  • [1]

    F. Abeet al. (CDF), Phys. Rev. Lett.81, 2432-2437 (1998), arXiv:hepex/9805034[hep-ex

  • [2]

    F. Abeet al. (CDF), Phys. Rev. D58, 112004 (1998), arXiv:hep-ex/9804014[hep-ex

  • [3]

    P.A. Zylaet al. (Particle Data Group), Prog. Theor. Exp. Phys. 2020, 083C01 (2020) to be published

  • [4]

    J. Leeset al. (BaBar), Phys. Rev. Lett.109, 101802 (2012), arXiv:1205.5442[hep-ex

  • [5]

    A. Abdesselamet al. (Belle), arXiv: 1904.08794 [hep-ex]

  • [6]

    R. Aaijet al. (LHCb), Phys. Rev. Lett.120, 171802 (2018), arXiv:1708.08856[hep-ex

  • [7]

    X. Q. Li, Y. D. Yang, and X. Zhang, JHEP08, 054 (2016), arXiv:1605.09308[hep-ph

  • [8]

    R. Alonso, B. Grinstein, and J. M. Camalich, Phys. Rev. Lett.118, 081802 (2017), arXiv:1611.06676[hep-ph

  • [9]

    CEPC Study Group, arXiv: 1811.10545 [hep-ex]

  • [10]

    Line Shape Sub-Group of the LEP Electroweak Working Group, DELPHI, LEP, ALEPH, OPAL, L3 Collaboration, Combination procedure for the precise determination of Z boson parameters from results of the LEP experiments, arXiv: hep-ex/0101027 [hep-ex]

  • [11]

    M. Acciarriet al. (L3), Phys. Lett. B396, 327-337 (1997)

  • [12]

    M. L. Mangano and S. Slabospitsky, Phys. Lett. B410, 299-303 (1997), arXiv:hep-ph/9707248[hep-ph

  • [13]

    A. Akeroyd, C. H. Chen, and S. Recksiegel, Phys. Rev. D77, 115018 (2008), arXiv:0803.3517[hep-ph

  • [14]

    J. Jiang, L. B. Chen, and C. F. Qiao, Phys. Rev. D91, 034033 (2015), arXiv:1501.00338[hep-ph

  • [15]

    B. Colquhounet al. (HPQCD), Phys. Rev. D91, 114509 (2015), arXiv:1503.05762[hep-lat

  • [16]

    V. V. Kiselev, A. E. Kovalsky, and A. K. Likhoded, Nucl. Phys. B585, 353-382 (2000), arXiv:hep-ph/0002127[hep-ph

  • [17]

    J. Kalinowski, Phys. Lett. B245, 201-206 (1990)

  • [18]

    W. S. Hou, Phys. Rev. D48, 2342 (1993)

  • [19]

    Z. R. Huang, Y. Li, C. D. Luet al., Phys. Rev. D98, 095018 (2018), arXiv:1808.03565[hep-ph

  • [20]

    K. Cheung, Z. R. Huang, H. D. Let al., arXiv: 2002.07272 [hep-ph]

  • [21]

    The Pythia Group, An Introduction to PYTHIA 8.2, Comput. Phys. Commun.191(2015)

  • [22]

    W. Kilian, T. Ohl, and J. Reuter, WHIZARD: simulating multiparticle processes at LHC and ILC, Eur. Phys. J. C71, 1742 (2011)

  • [23]

    C.D. Fu, Full simulation software at CEPC,http://cepcdoc.ihep.ac.cn/DocDB/0001/000167/001, Accessed 23 Oct 2017

  • [24]

    S. Agostinelliet al., Geant4-a simulation toolkit, Nucl. Instrum. Methods Phys. Res. Sect. A Accel. Spectrom. Detect. Assoc. Equip.506, 250–303 (2003)

  • [25]

    M.Q. Ruanet al., Eur. Phys. J. C78, 426 (2018)

  • [26]

    D. Yuet al., Eur. Phys. J. C77, 591 (2017), arXiv:1701.07542

  • [27]

    T. Suehara and T. Tanabe, LCFIPlus: A framework for jet analysis in linear collider studies, Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Feburary, 2016

  • [28]

    A. Hockeret al., TMVA-toolkit for multivariate data analysis, physics/0703039, CERN-OPEN-2007-007

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