In the standard model, the Higgs field is an SU (2) doublet (i.e. the standard representation with two complex components called isospin), which is a scalar under Lorentz transformations. Its electric charge is zero; its weak isospin is ⁠ 1 / 2 ⁠ and the third component of weak isospin is − ⁠ 1 / 2 ⁠ ; and its weak hypercharge (the charge for the U (1) gauge group defined up to an arbitrary multiplicative constant) is 1. Under U (1) rotations, it is multiplied by a phase, which thus mixes the real and imaginary parts of the complex spinor into each other, combining to the standard two-component complex representation of the group U (2).