Name: Dimitry Fedorov Date: 05/15/08-08:55:04 AM Z
This code will work and gives needed result:
ma = DiracSimplify[
SpinorUBar[k1, m].DiracMatrix[mu].SpinorU[p1,
m]] DiracSimplify[
SpinorUBar[k2, m].DiracMatrix[mu].SpinorU[p2,
m]];
mac = ComplexConjugate[ma] /. {mu -> nu};
amps = Simplify[Contract[FermionSpinSum[ma mac] /.
DiracTrace -> TR]]
or so:
ma1 = DiracSimplify[SpinorUBar[k1,
m].DiracMatrix[mu].SpinorU[p1, m]]
ma2 = DiracSimplify[SpinorUBar[k2,
m].DiracMatrix[mu].SpinorU[p2, m]]
mac1 = ComplexConjugate[ma1] /. {mu -> nu}
mac2 = ComplexConjugate[ma2] /. {mu -> nu}
amps1 = Simplify[FermionSpinSum[ma1 mac1] /. DiracTrace ->
TR]
amps2 = Simplify[FermionSpinSum[ma2 mac2] /. DiracTrace ->
TR]
Simplify[Contract[amps1 amps2]]
-—- Original Message —–
From: “ossama”
<[noreply_at_HIDDEN-E-MAIL]>
To:
<[feyncalc_at_HIDDEN-E-MAIL]>
Sent: Thursday, May 15, 2008 1:06 AM
Subject: FermionSpinSum gives unwanted results
> hello,
> i have:
>
Ma=SpinorUBar[k1,m].DiracMatrix[mu].SpinorU[p1,m].SpinorUBar[k2,m].DiracMatrix[mu].SpinorU[p2,m]
>
> Mac=ComplexConjugate[Ma] /.mu->nu
>
> amp=Ma Mac //Contract
>
> amps=FermionSpinSum[amp]
>
> but the output of FermionSpinSum does not has Traces, the above code
is
> for calculating the unpolorized feynman amplitude of the Moller
process.
> can you help me
>