Family gauge symmetry and Koide's mass formula

Koide's mass formula is an empirical relation among the charged lepton masses which holds with a striking precision. We propose a mechanism for cancelling the QED correction to Koide's formula. This is discussed in an effective theory with U(3)U(3) family gauge symmetry and a scenario in which this symmetry is unified with SU(2)LSU(2)L symmetry at 102–103 TeV102–103 TeV scale.