**Next message:**Hrayr Matevosyan: "Frustrating problem with Tr[0.]"**Previous message:**FengF: "Tr and Calc"**In reply to:**FengF: "Tr and Calc"**Messages sorted by:**[ date ] [ thread ] [ subject ] [ author ]**Mail actions:**[ respond to this message ] [ mail a new topic ]

Hi,

first of all: you seem to have errors in your

input.

You write:

Lepton=FV[k1,mu]FV[k2,nu]+FV[k2,mu]VF[k1,nu]-SP[k1,k2]MT[mu,nu]

Quark=FV[p3,alhpa]FV[k,beta]+FV[k,alpha]VF[p3,beta]-SP[k,p3]MT[alpha,beta]

AA=GA[mu].(GS[p1+p3-k]+m).GS[alpha].(GS[p1]+m).GS[5].GS[S].GA[nu].(GS[k+p2-p3]+m).GA[beta].(GS[p2]-m)

However, I guess what you mean is:

Lepton = FV[k1, mu]*FV[k2, nu] + FV[k2, mu]*FV[k1, nu] -

SP[k1, k2]*MT[mu, nu];

Quark = FV[p3, alpha]*FV[k, beta] + FV[k, alpha]*FV[p3, beta] -

SP[k, p3]*MT[alpha, beta];

AA = GA[mu] . (GS[p1 + p3 - k] + m) . GA[alpha] . (GS[p1] + m) .

GA[5] . GS[S] . GA[nu] . (GS[k + p2 - p3] + m) . GA[beta] .

(GS[p2] - m);

r1=Calc[Lepton Quark AA];

r2=TR[r1]//Expand;

(* ---------------- *)

It is probably better for more complicated traces to

first use Calc or DiracSimplify and Contract before invoking TR.

Still, due to the Schouten identity the result may be

seemingly different.

You probably also should use energy-momentum conservation.

You have k1,k2,p3,k,p1,p3 and S as four-vectors.

They probably are not independent.

Rolf

Rolf

**Next message:**Hrayr Matevosyan: "Frustrating problem with Tr[0.]"**Previous message:**FengF: "Tr and Calc"**In reply to:**FengF: "Tr and Calc"**Messages sorted by:**[ date ] [ thread ] [ subject ] [ author ]**Mail actions:**[ respond to this message ] [ mail a new topic ]

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