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Prospects for \( {B}_c^{+} \)→ τ +ντ at FCC-ee

A preprint version of the article is available at arXiv.

Abstract

This paper presents the prospects for a precise measurement of the branching fraction of the leptonic \( {B}_c^{+} \) → τ +ντ decay at the Future Circular Collider (FCC-ee) running at the Z -pole. A detailed description of the simulation and analysis framework is provided. To select signal candidates, two Boosted Decision Tree algorithms are employed and optimised. The first stage suppresses inclusive \( b\overline{b} \), \( c\overline{c} \), and \( q\overline{q} \) backgrounds using event-based topological information. A second stage utilises the properties of the hadronic τ + → π+π+π\( \overline{\nu} \)τ decay to further suppress these backgrounds, and is also found to achieve high rejection for the B+ → τ +ντ background. The number of \( {B}_c^{+} \)→ τ +ντ candidates is estimated for various Tera-Z scenarios, and the potential precision of signal yield and branching fraction measurements evaluated. The phenomenological impact of such measurements on various New Physics scenarios is also explored.

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Amhis, Y., Hartmann, M., Helsens, C. et al. Prospects for \( {B}_c^{+} \)→ τ +ντ at FCC-ee. J. High Energ. Phys. 2021, 133 (2021). https://doi.org/10.1007/JHEP12(2021)133

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  • DOI: https://doi.org/10.1007/JHEP12(2021)133

Keywords

  • B physics
  • e +-e Experiments
  • Flavor physics
  • Tau Physics