I’m working on a quantum field theory calculation in Mathematica using FeynCalc, and I’m running into the following error:
Contract::fail: Error! Contract has encountered a fatal problem and must abort the computation. The problem reads: Something went wrong during prepareProductContractions. The error occurs when executing this line in my code:
Calc[FullSimplify[Y1]] /. momentumRules Here’s the relevant portion of my code:
(* Definitions for expressions *) expr1 = GS[p2] . GA[\[Nu]] . (a - b GA[5]) . (GS[p1] - GS[p3]); expr2 = GA[\[Mu]] . (a - b GA[5]) . GS[p1] . GA[\[Rho]] . (a - b GA[5]); expr3 = (GS[p1] - GS[p3]) . GA[\[Sigma]] . (a - b GA[5]); (* Trace calculation *) T1 = FullSimplify[TR[expr1 . expr2 . expr3]]; (* Additional expressions *) expr4 = -MT[\[Mu], \[Rho]] + Pair[Momentum[FV[p3, \[Mu]]], Momentum[FV[p3, \[Rho]]]]/MV^2; expr5 = -MT[\[Nu], \[Sigma]] +Pair[Momentum[FV[p1 + p2 - p3, \[Nu]]], Momentum[FV[p1 + p2 - p3, \[Sigma]]]]/MV^2; (* Final combination *) Y1 = T1 expr4 expr5; (* Momentum rules for simplification *) momentumRules = { Pair[Momentum[p1], Momentum[p1]] -> 0, Pair[Momentum[p2], Momentum[p2]] -> 0, Pair[Momentum[p3], Momentum[p3]] -> MV^2 }; (* Problematic line *) Calc[FullSimplify[Y1]] /. momentumRules I have tried using Calc in the line Y1 = T1 expr4 expr5; and I get the same error, but if I use in the line T1 = FullSimplify[TR[expr1 . expr2 . expr3]]; there are no issues. I applied momentumRules to FullSimplify[Y1] before passing it to Calc, but the error still occurs.
simplifiedY1 = FullSimplify[Y1] /. momentumRules; Calc[simplifiedY1] The substitutions with momentumRules also seem fine when applied to simpler expressions. My Mathematica version is 14.1 and FeynCalc version is 10.1.0.
