rhad: A program for the evaluation of the hadronic R-ratio in the perturbative regime of QCD Original Research Article

This paper describes the fortran program rhad which performs a numerical evaluation of the photon-induced hadronic R-ratio, R(s), related to the cross section for electron–positron annihilation, for a given center-of-mass energy s. In rhad the state-of-the-art perturbative corrections to R(s) are implemented and the running and decoupling of the strong coupling constant and the quark masses is automatically treated consistently. Several options allow for a flexible use of the program.