LHC di-lepton searches for Z^ bosons which explain measurements of b s l^+l^- transitions

Several current measurements of b s l^+l^- processes are in tension with Standard Model predictions, whereas others (e. g. RK and R₊^) are in reasonable agreement with them. We examine some recent Z^ models that fit the data as a whole appreciably better than the Standard Model, confronting the models with ATLAS resonance searches in the e^+e^- and ^+^- channels. The models are constrained by both channels; we find that the lower limit on the Z^ mass Mₙ^ is 0. 8-1. 8 TeV at the 95\% confidence level, depending upon the model. We provide sensitivity estimates for the HL-LHC, which extend to more than double the current limits on Mₙ^.