Name: Pablo Sanchez Puertas (email_not_shown)
Date: 02/01/17-03:09:45 PM Z


Hello again!

Thanks for the long answer and explanations. As I said, don't worry
about the implementation in FeynCalc: I understand that such a task
would represent quite some work and I already managed myself to get
the numerics for the particular cases I need.
Moreover, I could check that, as you said, TID[] works propperly
whenever non-vanishing Gram determinants appear; in that case the
option UsePaVeBasis->True does the work perfectly anyway. So I guess
that is a nice and general advice.

On the other hand, concerning the current implementation, as I said,
there are still some terms which are missing and not included in the
references you showed me, but which appear in
http://dx.doi.org/10.1016/S0550-3213(03)00184-6
(still, as far as I know, not using DR for IR divergences). You could,
for instance, compare numerically with the result obtained from TID[]
and evaluating it numerically with LoopTools. In that sense, I thought
that would be worthy in the new version that OneLoop[] does not either
produce any output for the tensor integrals or produce some warning.

At the moment, I could not come up with an easy and systematic mehtod
to do the reduction of tensor integrals and I have not used DR for IR
divergences, so I cannot help with the implementation. Anyhow, if in
the future I can come up with some method, I will let you know.

Thanks a lot and congrats for the support,
Pablo



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