Where is the gauge field; is the weak hypercharge (the generator of the group); is the three-component gauge field; and the components of are the Pauli matrices (infinitesimal generators of the group) whose eigenvalues give the weak isospin. Note that we have to redefine a new symmetry of "weak hypercharge", different from QED, in order to achieve the unification with the weak force. The electric charge , third component of weak isospin (also called or ) and weak hypercharge are related by