Physical Review Letters, cilt.113, sa.15, 2014 (SCI-Expanded)
A measurement of the ratio of the branching fractions of the B+→K+μ+μ- and B+→K+e+e- decays is presented using proton-proton collision data, corresponding to an integrated luminosity of 3.0fb-1, recorded with the LHCb experiment at center-of-mass energies of 7 and 8 TeV. The value of the ratio of branching fractions for the dilepton invariant mass squared range 1