A follow-up on this 5-year old question: With FeynCalc 9.3 one can
input such scalar product using SP (or SPD), *if* the c-numbers
a and b are declared to have DataType FCVariable:
DataType[a, FCVariable] = True;
DataType[b, FCVariable] = True;
SP[a p1, b p2] // ExpandScalarProduct
yields
a b Pair[Momentum[p1], Momentum[p2]]
as expected.
Cheers
Vladyslav
> Hi,
>
> I have a very simple question.
>
> I compute the scalar product of two vectors p1 and p2, but each of them multiplied by Reals a, b :
> i.e. SP[a p1, b p2]
> I expect (a*b p1.p2) but I get (a p1).(b p2)
> How do I tell FeynCalc that a,b are to be treated as Reals?
>
> Explicitly doing SP[3 p1, 4 p2] gives me 12 p1.p2 as expected.
>
> Thanks for any help.
>
> Shrihari
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