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 $\mathcal{ O}(10^{ -9})$ for the $Z$ couplings to $cu$ and $sd$, $\mathcal{ O}(10^{ -7})$ for $bd$, $\mathcal{ O}(10^{ -6})$ for $bs$, and $\mathcal{ O}(10^{ -3})$ for $tu$ and $tc$. Overall, low-energy flavor experiments provide significantly stronger constraints on these FV couplings than current collider searches.
Categories: hep-ph hep-ex