LOOL: Mathematica Package for Evaluating Leading Order One Loop Functions

One-loop functions with loop masses larger than external masses and momenta can always be expanded in terms of external masses and momenta. The precision requested for observables determines the number of the expansion terms retained in the evaluation. The evaluation of these expansion terms turns out to be much simpler than the exact evaluation of the corresponding one-loop function. Here we present the program which evaluates those expansion terms. This Mathematica package provides two subroutines. First one performs analytical evaluation of basic one loop integrals. The second one is used to construct composite functions out of those integrals. Composite functions thus obtained are ready for numerical evaluation with literary no time consumption.