Dear Vladyslav,
Thank you very much for your quick reply. It helps a lot.
However, when i try to obtain the analytic expressions of triangle diagram mentioned in the previous email, I also encountered two questions about PaXDiLog.
In order to avoid unexpected results when performing Dimension -> 4, I use the recommended FeynHelper--Package-X.
When I do this, the treatment of pave coefficient C0 is necessary.
In my case, (I am handling the two-nucleon scattering with two-pion exchange.
mN, mpi deonte as nucleon and pion masses, p4 is the momentum of outgoing nucleon, q is the transfer momentum between two nucleons.)
XC0 = C0[p4^2, q^2, (p4+q)^2, mN^2, mpi^2, mpi^2]
should be replaced by using
XC0Re = PaXEvaluate[XC0, PaXC0Expand -> True]//Normal
Apparently, the output is lengthy with conditions.
Then, perform the 1/mN expansion,
Series[XC0Re, {mN, infty, 0}]//Normal
The result always contains Li2 functions (PaXDiLog).
1) How one can transfer PaXDiLog to PolyLog?
Furthermore, when I do the numerical evaluation for checking,
I also find another problem about PaXDiLog.
2) e.g. PaXDiLog[Complex[-1,-6],-0.2], it cannot give a numerical value.
Could you kindly let me know how to handle these problem?
Merry Christmas and happy new year.
Cheers,
Xiu-Lei
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