Bounds on vector leptoquarks

We derive bounds on vector leptoquarks coupling to the first generation, using data from low energy experiments as well as from high energy accelerators. Similarly to the case of scalar leptoquarks, we find that the strongest indirect bounds arise from atomic parity violation and universality in leptonic π decays. These bounds are considerably stronger than the first direct bounds of the DESY ep collider HERA, restricting vector leptoquarks that couple with electromagnetic strength to right-handed quarks to lie above 430 GeV or 460 GeV, and leptoquarks that couple with electromagnetic strength to left-handed quarks to lie above 1.3 TeV, 1.2 TeV, and 1.5 TeV for the SU(2${)}_{\mathit{W}}$ singlet, doublet, and triplet, respectively.