IV.D117 — Left-Handed Doublets

Left-handed fermions form SU(2)_L doublets: three lepton doublets (nu_e/e, nu_mu/mu, nu_tau/tau) and three quark doublets (u/d, c/s, t/b). Upper has I_3=+1/2 (L+), lower has I_3=-1/2 (L-).