**Next message:**zhangyaworld: "Re:Eight Gamma Matrix involving Gamma5, within t'Hooft Scheme"**Previous message:**V. Shtabovenko: "Re: Is there a method in FeynCalc for collecting like powers of four vectors? rizikmat@msu.edu"**Next in thread:**zhangyaworld: "Re:Eight Gamma Matrix involving Gamma5, within t'Hooft Scheme"**Maybe reply:**zhangyaworld: "Re:Eight Gamma Matrix involving Gamma5, within t'Hooft Scheme"**Messages sorted by:**[ date ] [ thread ] [ subject ] [ author ]**Mail actions:**[ respond to this message ] [ mail a new topic ]

Hi Vladyslav,

I have two problem here.

====================First Problem====================

I've found a wired problem about the equivalence between GA[6] and (1+GA5)/2 (and GA[7]) within t'Hooft Scheme, i.e. with

$BreitMaison = True;

$Larin = False;

we have following results

1.for four gamma matrix, the results are the same:

A1 = DiracTrace[GAD[i1, i2].GA[6].GAD[i5, i6].GA[6],

DiracTraceEvaluate -> True];

A2 = DiracTrace[

GAD[i1, i2].((1 + GA[5])/2).GAD[i5, i6].((1 + GA[5])/2),

DiracTraceEvaluate -> True];

A1 - A2

0

2. for >= 6 gamma matrix, the terms involving Levi-Civita symbol are different:

A1 = DiracTrace[GAD[i1, i2, i3].GA[6].GAD[i5, i6, i7].GA[6],

DiracTraceEvaluate -> True];

A2 = DiracTrace[

GAD[i1, i2, i3].((1 + GA[5])/2).GAD[i5, i6, i7].((1 + GA[5])/2),

DiracTraceEvaluate -> True];

A1 - A2 // Simplify // Collect[#, Eps[___]] &

-2 I Eps[LorentzIndex[i2], LorentzIndex[i3], LorentzIndex[i6],

LorentzIndex[

i7]] (Pair[LorentzIndex[i1, -4 + D], LorentzIndex[i5, -4 + D]] -

Pair[LorentzIndex[i1, D], LorentzIndex[i5, D]]) (+...)

Tow common features, the first is this only happens for those involving two Gamma5 cases, and the second is that the results only differ in those involving Levi-Civita symbol.

(Actually what I want to calculate is a trace involving eight gamma matrix and two GA[6]).

So if I want to split the terms with/without involving Gamma5, what should I do?

Thanks!

====================Second Problem====================

The second problem is about a warning when I type

?$BreitMaison

The warning reads as

"The Breitenlohner-Maison gamma5 scheme is currently not supported by the Dirac algebra functions. Use Tracer if you need it."

So will it be problematic if I stick to use DiracTrace[x___]//TID[#, q, UsePaVeBasis -> True] & // ToPaVe[#, q] & to get the One-Loop integrals?

Thanks a lot!

Best wishes

Ya

**Next message:**zhangyaworld: "Re:Eight Gamma Matrix involving Gamma5, within t'Hooft Scheme"**Previous message:**V. Shtabovenko: "Re: Is there a method in FeynCalc for collecting like powers of four vectors? rizikmat@msu.edu"**Next in thread:**zhangyaworld: "Re:Eight Gamma Matrix involving Gamma5, within t'Hooft Scheme"**Maybe reply:**zhangyaworld: "Re:Eight Gamma Matrix involving Gamma5, within t'Hooft Scheme"**Messages sorted by:**[ date ] [ thread ] [ subject ] [ author ]**Mail actions:**[ respond to this message ] [ mail a new topic ]

*
This archive was generated by hypermail 2b29
: 07/23/18-07:00:02 PM Z CEST
*