Documentation unfinished ....; see also the old FeynCalc documentation at http://www.mertig.com/oldfc. 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:

is calculated in D dimensions has changed compared to the old FeynCalc version. Please keep in mind that the issue of schemes is inherintly tricky.

Description

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.

Examples

Remember that FAD[{q,mf},{q-k,mf}] is a fast possibility to enter

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

NTerms

OneLoopSimplify