C0[p10, p12, p20, m1^2, m2^2, m3^2] is the scalar Passarino - Veltman function. 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.
See also: B0, D0, PaVe, PaVeOrder.
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