Estimate vector-meson mixing with the Standard Model Z boson

Estimate the mixing angle between the dark rho vector meson and the Standard Model Z boson in the confining dark sectors, accounting for its dependence on the numbers of dark colors and dark flavors and for non-perturbative uncertainties away from the light-quark limit.

Background

The dark rho meson may appear at colliders as a Z'-like dilepton resonance through mixing with the Standard Model Z boson. The paper notes that a mixing angle of approximately 0.01 could evade current Sequential Standard Model Z' bounds.

A quantitative estimate is unresolved because the mixing depends on the dark-sector parameters N_c and N_f and becomes difficult to control non-perturbatively outside the light-quark limit.

References

We leave estimation of this mixing angle to future work, as there are subtleties due to dependence on $N_c$ and $N_f$ (see, e.g., ), as well as non-perturbative uncertainties that become difficult to control away from the light-quark limit.

— For Whom the Xenon Recoils: Magnetic Inelastic Dark Baryons  (2609.09107 - Asadi et al., 8 Sep 2026) in Section 'Collider Signals', item 'Vector mesons'