Novel and Updated Bounds on Flavor-Violating Z Interactions in the Quark Sector

We derive bounds on the flavor-violating (FV) couplings of the Z boson to quarks and present future sensitivity projections. Our analysis shows that the current bounds on the FV couplings are O(10⁻⁹) for the Z couplings to $cu$ and $sd$, O(10⁻⁷) for $bd$, O(10⁻⁶) for $bs$, and O(10⁻³) for $tu$ and $tc$. Overall, low-energy flavor experiments provide significantly stronger constraints on these FV couplings than current collider searches.