The minimum of the potential is degenerate with an infinite number of equivalent ground state solutions, which occurs when φ φ † † φ φ = μ μ 2 2 λ λ . It is possible to perform a gauge transformation on φ φ such that the ground state is transformed to a basis where φ φ 1 = φ φ 2 = φ φ 4 = 0 and φ φ 3 = μ μ λ λ ≡ ≡ v . This breaks the symmetry of the ground state. The expectation value of φ φ now becomes ⟨ ⟨ φ φ ⟩ ⟩ = 1 2 ( 0 v ) , where v has units of mass and sets the scale of electroweak physics. This is the only dimensional parameter of the Standard Model and has a measured value of ~ 246 GeV/ c.