The choice of free parameters is somewhat arbitrary. In the table above, gauge couplings are listed as free parameters, therefore with this choice Weinberg angle is not a free parameter - it is defined as formula_74. Likewise, fine structure constant of QED is formula_75. Instead of fermion masses, dimensionless Yukawa couplings can be chosen as free parameters. For example, electron mass depends on the Yukawa coupling of electron to Higgs field, and its value is formula_76. Instead of the Higgs mass, the Higgs self-coupling strength formula_77, which is approximately 0.129, can be chosen as a free parameter. Instead of the Higgs vacuum expectation value, formula_78 parameter directly from Higgs self-interaction term formula_79 can be chosen. Its value is formula_80, or approximately formula_81 GeV.