| Article | |
| Report number | arXiv:2305.02998 ; TTP23-015 ; P3H-23-28 |
| Title | Prospects for $B_c^+$ and $B^+\rightarrow \tau ^+ \nu _\tau $ at FCC-ee |
| Author(s) | Zuo, Xunwu (KIT, Karlsruhe, ETP) ; Fedele, Marco (KIT, Karlsruhe, TTP) ; Helsens, Clément (KIT, Karlsruhe ; Ecole Polytechnique, Lausanne ; CERN) ; Hill, Donal (Ecole Polytechnique, Lausanne) ; Iguro, Syuhei (KIT, Karlsruhe, TTP ; KIT, Karlsruhe, IAP) ; Klute, Markus (KIT, Karlsruhe) |
| Publication | 2024-01-26 |
| Imprint | 2023-05-04 |
| Number of pages | 28 |
| Note | 39 pages, 19 figures, 5 tables |
| In: | Eur. Phys. J. C 84 (2024) 87 |
| DOI | 10.1140/epjc/s10052-024-12418-0 |
| Subject category | hep-ph ; Particle Physics - Phenomenology ; hep-ex ; Particle Physics - Experiment |
| Study | CERN FCC |
| Abstract | The prospects are presented for precise measurements of the branching ratios of the purely leptonic $B_c^+ \to \tau^+ \nu_\tau$ and $B^+ \to \tau^+ \nu_\tau$ decays at the Future Circular Collider (FCC). This work is focused on the hadronic $\tau^{+} \to \pi^+ \pi^+ \pi^- \bar{\nu}_\tau$ decay in both $B_c^+ \to \tau^+ \nu_\tau$ and $B^+ \to \tau^+ \nu_\tau$ processes. Events are selected with two Boosted Decision Tree algorithms to optimise the separation between the two signal processes as well as the generic hadronic $Z$ decay backgrounds. The range of the expected precision for both signals are evaluated in different scenarios of non-ideal background modelling. This paper demonstrates, for the first time, that the $B^+ \to \tau^+ \nu_\tau$ decay can be well separated from both $B_c^+ \to \tau^+ \nu_\tau$ and generic $Z\to b\bar{b}$ processes in the FCC-ee collision environment and proposes the corresponding branching ratio measurement as a novel way to determine the CKM matrix element $|V_{ub}|$. The theoretical impacts of both $B^+ \to \tau^+ \nu_\tau$ and $B_c^+ \to \tau^+ \nu_\tau$ measurements on New Physics cases are discussed for interpretations in the generic Two-Higgs-doublet model and leptoquark models. |
| Copyright/License | preprint: (License: arXiv nonexclusive-distrib 1.0) publication: © 2024-2025 The Author(s) (License: CC-BY-4.0) |
Corresponding record in: Inspire
Record created 2024-02-07, last modified 2024-10-02
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