Name: Vladyslav Shtabovenko Date: 05/10/17-09:47:05 PM Z


Hi,

sorry for the late reply. I’m afraid that with FeynCalc 8.2 the
reordering of Spinors (due to DiracSimplify applying Sirlin’s
identitites) cannot be easily disabled.

In FeynCalc 9 and above there is an option SirlinRelations, so that
one could either set

SetOptions[DiracSimplify, SirlinRelations -> False]

or (which is even better) use TID instead of OneLoop.

Cheers,
Vladyslav

Am 06.05.2017 um 05:28 schrieb Monica Salinas:
> Hi!
> IŽm using mathematica 8.2.
> I have an expression like this
>
> Spinor[1]…Spinor[2]*Spinor[3]*Spinor[4]
>
> But when I introduce this in OneLoop instruction, at the end Mathematica changes the order of the spinors
>
> Spinor[4]…Spinor[2]*Spinor[3]*Spinor[1]
>
> How can I avoid this?
>