$LeviCivitaSign
is a global variable that determines the sign in the result of a Dirac trace of four gamma matrices and . $LeviCivitaSign
is by default set to -1
which corresponds to the convention TR[LC[a,b,c,d,5]] = -4*I*Eps[a,b,c,d]
. Setting $LeviCivitaSign=-I
will switch to the FORM-convention.
Overview, LC, Eps, DiracTrace.
$LeviCivitaSign
[GA[\[Mu], \[Nu], \[Rho], \[Sigma], 5]] // DiracSimplify DiracTrace
This sets the same convention as in FORM
= -I;
$LeviCivitaSign
[GA[\[Mu], \[Nu], \[Rho], \[Sigma], 5]] // DiracSimplify DiracTrace
Back to the standard value
= -1; $LeviCivitaSign