Test of Lepton Flavor Universality with Bs0 →φℓ+ℓ- Decays

Lepton flavor universality in rare b→s transitions is tested for the first time using Bs0 meson decays. The measurements are performed using pp collision data collected by the LHCb experiment between 2011 and 2018, corresponding to a total integrated luminosity of 9 fb-1. Branching fraction ratios between the Bs0→φe+e- and Bs0→φμ+μ- decays are measured in three regions of dilepton mass squared, q2, with 0.1