Name: zwhuang (email_not_shown)
Date: 05/15/04-04:29:24 PM Z

Hi,

I have some questions about DiracTrace & TR functions. Here "t" and "s" are only different in
the trace function DiracTrace or TR. By using OneLoop, I suppose the result "rst1-rst2" should
be zero, but the output is not.

(****************************************************************************)
\!\(t = I\ \(el\^2\/\(16\ \(Pi\^4\) \((
1 - D)\)\)\) FAD[{q, mf}, {q - k, mf}] DiracTrace[\((mf + GS[q -
k])\) . GA[¦Ì] . \((mf + GS[q])\) .
GA[¦Ì]]\ // \ FCI\[IndentingNewLine]
s = I\ \(el\^2\/\(16\ \(Pi\^4\) \((1 - D)\)\)\) FAD[{q,
mf}, {q - k, mf}] TR[\((mf + GS[q - k])\) . GA[¦Ì] . \((mf +
GS[q])\) . GA[¦Ì]]\ // \ FCI\)
OneLoop[q, t]
rst1 = FullSimplify[%]
OneLoop[q, s]
rst2 = FullSimplify[%]
rst1 - rst2 // Simplify
(****************************************************************************)

The attachment is the full file (Trace.nb) with outputs.

Anther question is about the option "TraceOfOne". FeynCalc sets "TraceOfOne->4" in both
DiracTrace & TR functions in the usual cases. What I want to know is wether I should
set "TraceOfOne->D" when I do some calculations in D-dimension.

Best regards,

Zhiwei Huang,
Wuhan University, PRC

• application/mathematica attachment: Trace.nb

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