Name: Fabrizio Nesti (email_not_shown)
Date: 06/21/11-05:51:36 PM Z


Dear Rolf,

I seem to find a weird behavior of FeynCalc when calculating a sim[ple self-energy, due to a W loop: changing Dimension->4 to Dimenson->D the loop variable results in the output (and it should not!).

 INT[X_] := OneLoop[k, X, Dimension -> D, OneLoopSimplify -> False,
    ReduceGamma -> True];

 AMPLITUDE =
  Contract[GAD[\[Alpha]].PL.(GSD[k] + GSD[p] +
      mi).GAD[\[Beta]].PL.FAD[{k + p, mi}].\[CapitalDelta]g[k,
     0, \[Alpha], \[Beta], M, 1]]
 
 INT[AMPLITUDE] // PaVeReduce // Simplify

Gives (notice the kslash!)

 (I \[Pi] (-(M^2-mi^2+p^2) Subscript[B, 0](p^2,M^2,mi^2)+(M^2-mi^2) Subscript[B, 0](0,M^2,mi^2)+p^2) (-(\[Gamma]\[CenterDot]k).\[Gamma]^5+\[Gamma]\[CenterDot]k-(\[Gamma]\[CenterDot]p).\[Gamma]^5+\[Gamma]\[CenterDot]p))/(2 p^2)

Any hint? Thanks a lot!

Fabrizio

PS: Putting Dimension->4 the result has no kslash (but the finite part seems not to agree with the textbook result....

PPS: running FeynCalc 8b2 on Mathematica8



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