Prospects for $B_c^{+}$ and $B^{+}\to {\tau }^{+}{\nu }_{\tau }$ at FCC-ee

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.

39 pages, 19 figures, 5 tables

References in corpus (17)

• An Introduction to PYTHIA 8.2
• Measurement of the branching ratio of ${\bar{B}}^0\to D^{\ast +}{\tau }^{-}{\bar{\nu }}_{\tau }$ relative to ${\bar{B}}^0\to D^{\ast +}{\ell }^{-}{\bar{\nu }}_{\ell }$ decays with a semileptonic tagging method
• Averages of $b$-hadron, $c$-hadron, and $\tau$-lepton properties as of 2021
• Confronting lepton flavor universality violation in B decays with high-$p_T$ tau lepton searches at LHC
• The lifetime of the $B_c^{-}$ meson and the anomalies in $B\to D^{(\ast )}\tau \nu$
• Measurement of the $\tau$ lepton polarization and $R(D^{\ast })$ in the decay $\bar{B}\to D^{\ast }{\tau }^{-}{\bar{\nu }}_{\tau }$ with one-prong hadronic $\tau$ decays at Belle
• Renormalization-group evolution of new physics contributions to (semi)leptonic meson decays
• B-meson decay constants: a more complete picture from full lattice QCD
• Inclusive semileptonic B decays and the determination of |V_ub|
• With or without U(2)? Probing non-standard flavor and helicity structures in semileptonic B decays
• Observation of the decay ${\Lambda }_b^0\to {\Lambda }_c^{+}{\tau }^{-}{\overline{\nu }}_{\tau }$
• Impact of ${\Lambda }_b\to {\Lambda }_c\tau \nu$ measurement on New Physics in $b\to cl\nu$ transitions
• Towards ruling out the charged Higgs interpretation of the $R_{D^{(\ast )}}$ anomaly
• Non-resonant new physics search at the LHC for the $b\to c\tau \nu$ anomalies
• Revival of $H^{-}$ interpretation of $R_{D^{(\ast )}}$ anomaly and closing low mass window
• Interpreting LHCb's ${\Lambda }_b\to {\Lambda }_c\tau \bar{\nu }$ measurement and puzzles in semileptonic ${\Lambda }_b$ decays
• Particle Identification at FCC-ee

Cited by in corpus (6)

• Global fit to $b\to c\tau \nu$ anomalies as of Spring 2024
• Testing Lepton Flavor Universality at the Electron-Ion Collider
• New opportunities for rare charm from $Z\to c\bar{c}$ decays
• Precision Tests in $b\to s{\ell }^{+}{\ell }^{-}$ ($\ell =e,\mu$) at FCC-ee
• The Simplest B Decay, Precisely
• Prospects of searches for invisible $B$-meson decays at FCC-ee