Documentation unfinished ....; see also the old FeynCalc documentation at NOTICE: While OneLoop is restricted to 't Hooft Feynman gauge the function OneLoopSimplify does not have this restriction (but is usually slower). OneLoop handles selfenergies, vertex and box-graphs (those only up to 3rd rank tensor in the integration variable).

WARNING: If you encounter anomalies:

[Graphics:Images/index_gr_1.gif] is calculated in D dimensions has changed compared to the old FeynCalc version. Please keep in mind that the issue of [Graphics:Images/index_gr_2.gif]schemes is inherintly tricky.


OneLoop[q, amplitude] calculates the one-loop Feynman diagram amplitude (n-point, where n<=4 and the highest tensor rank of the integration momenta (after cancellation of scalar products) may be 3; unless OneLoopSimplify is used).

The argument q denotes the integration variable, i.e., the loop momentum. OneLoop[name, q, amplitude] has as first argument a name of the amplitude. If the second argument has head FeynAmp then OneLoop[q, FeynAmp[name, k, expr]] and OneLoop[FeynAmp[name, k, expr]] tranform to OneLoop[name, k, expr].


See also: B0, C0, D0, OneLoopSimplify, TID, TIDL.


Remember that FAD[{q,mf},{q-k,mf}] is a fast possibility to enter [Graphics:Images/index_gr_10.gif]


The input to OneLoop may be in 4 dimensions, since the function changes the dimension of the objects automatically to the setting of the Dimension option (D by default).


The FeynCalc Book   previousNTerms   nextOneLoopSimplify

Converted from the Mathematica notebook OneLoop.nb