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arXiv · 2503.21319

A $B-$anomaly motivated $Z^\prime$ boson at the energy and precision frontiers

Ben Allanach·Christoph Englert·Wrishik Naskar
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Abstract

TeV-scale $Z^\prime$ bosons with family-dependent couplings can explain some anomalies inferred from $B-$meson measurements of processes involving the $b \rightarrow s \ell^+\ell^-$ transition. A $Z^\prime$ originating from kinetically-mixed spontaneously broken $U(1)_{B_3-L_2}$ gauge symmetry has been shown to greatly ameliorate global fits~\cite{Allanach:2024ozu} in a `flavour-preferred' region of parameter space. We provide an exploration of this region at the high luminosity (HL-)LHC with particular attention to which signals could be verified across different discovery modes. Even if the HL-LHC does not discover the $Z^\prime$ boson in a resonant di-lepton channel, a FCC-ee $Z$-pole run would detect oblique corrections to the electroweak precision observables (EWPOs). Changes due to $Z^\prime$-induced non-oblique corrections are unlikely to be detected, to within experimental precision. In any case, the extended discovery potential offered by a 100 TeV $pp-$collider would afford sensitivity to the entire flavour-preferred region and enable a fine-grained and forensic analysis of the~model.

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Ben Allanach, Christoph Englert, Wrishik Naskar. 2025-10-17. A $B-$anomaly motivated $Z^\prime$ boson at the energy and precision frontiers. https://doi.org/10.1016/j.physletb.2025.139928

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