Constraints on the malaphoric B 3 - L 2 model from di-lepton resonance searches at the LHC.

Abstract

We confront the malaphoric B 3 - L 2 model with bounds coming from a search for resonances in the di-lepton channels at the 13 TeV LHC. In contrast to the original B 3 - L 2 model, the Z ' of the malaphoric B 3 - L 2 model has sizeable couplings to the lighter two families; these originate from order unity kinetic mixing with the hypercharge gauge boson and ameliorate the fit to lepton flavour universality measurements in B-meson decays. The Z ' coupling to the first two families of quark means that the resulting constraints from resonant di-lepton searches are stronger. Nevertheless, we find that for M Z ' > 2.8 TeV there remains a non-negligible region of allowed parameter space where the model significantly improves upon several Standard Model predictions for observables involving the b → s l + l - transition. We estimate that the 3000 fb - 1 HL-LHC will extend this sensitivity to M Z ' = 4.2 TeV.