Name: Carina Zanetti Date: 08/23/11-11:53:21 PM Z
I have different results when I calculate some traces if I use
Mathematica
5.2 or Mathematica 8.
For example when I calculate the following trace:
DS = DiracSigma[GA[k], GA[l]];
Simplify[TR[Contract[(DS.(GS[k - p] + m) + (GS[k
The output in Mathematica 5.2 is the following:
********************************Mathematica
5.2************************************************
\!\(16\ \[ImaginaryI]\ \((\(-3\)
Eps[LorentzIndex[c], Momentum[
k], Momentum[p], Momentum[y]]
Pair[LorentzIndex[a], \
LorentzIndex[b]] +
Eps[LorentzIndex[b], Momentum[k],
Momentum[
p], Momentum[y]]
Pair[LorentzIndex[a], LorentzIndex[c]] + 6\
\
Eps[LorentzIndex[b], LorentzIndex[c],
Momentum[k], Momentum[y]]\
Pair[LorentzIndex[a], Momentum[k]]
And the output using Mathematica 8 is:
*************************Mathematica
8*************************************************************
16 I (-3 Eps[LorentzIndex[c], Momentum[k],
Momentum[p],
Momentum[y]] Pair[LorentzIndex[a],
LorentzIndex[b]] +
3 Eps[LorentzIndex[b], Momentum[k],
Momentum[p], Momentum[y]] Pair[
LorentzIndex[a], LorentzIndex[c]] +
6 Eps[LorentzIndex[b], LorentzIndex[c],
Momentum[k],
Momentum[y]] Pair[LorentzIndex[a],
Momentum[k]] -
3 Eps[LorentzIndex[b], LorentzIndex[c],
Momentum[p],
Momentum[y]] Pair[LorentzIndex[a],
Momentum[k]] -
5 Eps[LorentzIndex[b], LorentzIndex[c],
Momentum[k],
Momentum[y]] Pair[LorentzIndex[a],
Momentum[p]] -
3 Eps[LorentzIndex[b], LorentzIndex[c],
Momentum[k],
Momentum[p]] Pair[LorentzIndex[a],
Momentum[y]] -
3 Eps[LorentzIndex[a], Momentum[k],
Momentum[p], Momentum[y]] Pair[
LorentzIndex[b], LorentzIndex[c]] -
3 Eps[LorentzIndex[a], LorentzIndex[c],
Momentum[p],
Momentum[y]] Pair[LorentzIndex[b],
Momentum[k]] +
5 Eps[LorentzIndex[a], LorentzIndex[c],
Momentum[k],
Momentum[y]] Pair[LorentzIndex[b],
Momentum[p]] +
3 Eps[LorentzIndex[a], LorentzIndex[c],
Momentum[k],
Momentum[p]] Pair[LorentzIndex[b],
Momentum[y]] +
3 Eps[LorentzIndex[a], LorentzIndex[b],
Momentum[p],
Momentum[y]] Pair[LorentzIndex[c],
Momentum[k]] -
5 Eps[LorentzIndex[a], LorentzIndex[b],
Momentum[k],
Momentum[y]] Pair[LorentzIndex[c],
Momentum[p]] +
3 Eps[LorentzIndex[a], LorentzIndex[b],
Momentum[k],
Momentum[p]] Pair[LorentzIndex[c],
Momentum[y]] +
Eps[LorentzIndex[a], LorentzIndex[b],
LorentzIndex[c],
Momentum[y]] (6 m^2 - 3 Pair[Momentum[k],
Momentum[k]] +
5 Pair[Momentum[k], Momentum[p]]) +
3 Eps[LorentzIndex[a], LorentzIndex[b],
LorentzIndex[c],
Momentum[p]] Pair[Momentum[k],
Momentum[y]] -
5 Eps[LorentzIndex[a], LorentzIndex[b],
LorentzIndex[c],
Momentum[k]] Pair[Momentum[p],
Momentum[y]])
******************************************************************************************************