feynlag.pheno.loop.A_half_zgamma¶ feynlag.pheno.loop.A_half_zgamma(x, y)[source]¶ Fermion form factor for $Zgamma$: $A_{1/2}^{Zgamma}=I_1(x,y)-I_2(x,y)$, with $x=4m^2/m_h^2$, $y=4m^2/m_Z^2$.