LOOL: Mathematica package for evaluating leading order one loop functions

摘要

One-loop functions with loop masses larger than external masses and momentacan always be expanded in terms of external masses and momenta. The precisionrequested for observables determines the number of the expansion terms retainedin the evaluation. The evaluation of these expansion terms turns out to be muchsimpler than the exact evaluation of the corresponding one-loop function. Herewe present the program which evaluates those expansion terms. This Mathematica package provides two subroutines. First one performsanalytical evaluation of basic one loop integrals. The second one is used toconstruct composite functions out of those integrals. Composite functions thusobtained are ready for numerical evaluation with literary no time consumption.