Sensitivity Analysis of Singlet Vector-Like B Quarks via Photon-Induced Processes at FCC--$\mu p$

This study presents a dedicated and systematic sensitivity analysis of a singlet-type vector-like $B$ quark at an FCC--$\mu p$ collider with a center-of-mass energy of $\sqrt{s}=24.5~\mathrm{TeV}$ via photon-induced production mechanisms. The analyses are based on the $B \to Zb$ decay and the lepton decay of the $Z$ boson on a clean and selective final state. In this regard, we observed that the applied kinematic cuts suppress the Standard Model backgrounds by several orders of magnitude while maintain high signal efficiency. Also, the obtained results show that for $\mathcal{L}=1000~\mathrm{fb^{-1}}$, even small coupling constant values in the mass range $M_B = 2$--$3$~TeV are accessible. In this context, an exclusion limit of $g^\ast \simeq 0.12$--$0.17$ at 95\% confidence level and a sensitivity in the range of $g^\ast \simeq 0.22$--$0.30$ for the $5\sigma$ discovery region are obtained. Moreover, the calculations indicate that scenarios with smaller ${\rm BR}(B\to Zb)$ values via increasing integrated luminosity values can be experimentally tested. As a result, the outputs of the study show that the FCC--$\mu p$ environment offers a unique and powerful discovery potential for vector-like quark searches that go beyond the current LHC limits and complement the decreasing sensitivity of the ep and $e^+e^-$ colliders in the high-mass regime. In this context, the findings suggest that the $\mu p$ colliders can be considered not only as a complementary option for the search of heavy new particles in the future accelerator programme, but also as a strategic discovery tool.