Name: Aliaksandr Dubrouski Date: 05/05/15-05:45:05 PM Z
2 Lingxiao Xu:
I would suggest to check how factors introduced by Peskin and Shroeder
are
related to the C_0 decomposition at certain relation of higgs and
quark
mass, the factor 3 came from there. That is not related to the Feyn
Calc
per se, it rather the matter of definition of the I(m_H/m_q) from
C_0.
2015-05-05 17:54 GMT+03:00 Lingxiao Xu <[noreply_at_HIDDEN-E-MAIL]>:
> 2 Aliaksandr:
>
> In the amplitude, the color factor is just Tr[T^a.T^b] which
equals to
> \delta^{ab}/2 exactly. So that in the amplitude squared after we
sum over
> color indexes a and b, we have \sum_{a,b} (\delta^{ab}/2)
> (\delta^{ab}/2)=2, so I just multiply 2 when the amplitude get
squared.
>
>
> Cheers!
>
> Lingxiao Xu
>
>
--
Regards,
Aliaksandr Dubrouski