FEYN CALC SYMBOL

C0


is the scalar Passarino-Veltman C_0function. The convention for the arguments is that if the denominator of the integrand has the form ([q^2-m1^2] [(q+p1)^2-m2^2] [(q+p2)^2-m3^2]), the first three arguments of C0 are the scalar products p10 = p1^2, p12 = (p1-p2).(p1-p2), p20 = p2^2.