Name: Vladyslav Shtabovenko (email_not_shown)
Date: 01/20/17-09:42:17 PM Z


Hi,

Am 20.01.2017 um 18:40 schrieb Pablo Sanchez Puertas:
> Hello again and thanks for your fast answer!
>
>
> I updated FeynCalc as suggested and the first problem is solved. As you said, is working fine :D
>
>
> Concerning the second part, I have some "minimal" working example that I could send to you to show the sign thing. Let me now, if you are interested, how I could send this to you (I am new to the forums and I don't know which option would be better).
>

You can simply attach the example to your e-mail, the mailing list
supports attachments.

> I was having a look at your implementation of Eq.(4.54) from the paper you mention: I am not sure that I fully understand the algorithm as implemented in the "NPointTo4Point.m" file you mention, but, could it be that there is possibly a minus sign missing?
> From the paper I understand:
>
> E0*Det[Y_{ij}] + D0(0)Det[Y_{ij}(/0)] + ... + D0(4)Det[Y_{ij}(/4)] = 0 +
>
> in which Y_{ij}(/n) is the Y_{ij} with the n-th row replaced by 1's, whereby
>
> E0*Det[Y_{ij}] = - ( D0(0)Det[Y_{ij}(/0)] + ... + D0(4)Det[Y_{ij}(/4)] ).
>
> (actually, implementing myself the previous Eqn. I can reproduce the "correct" sign) Is it the above "-" sign accounted for in getDet[] (line 70 in NPointTo4Point.m) ?
>

The implementation is not mine. It is there since very early versions of
FeynCalc, but I don't think that I ever used it.

Anyhow, please send me your examples and I will have a look.

Cheers,
Vladyslav

>
> Thanks,
> Pablo
>



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