Rhad: A program for the evaluation of the hadronic R-ratio in the perturbative regime of QCD

Abstract

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 \sqrt{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.

Comments: 40 pages, LaTeX. 18 ps-files included. Typos fixed, references updated. The program and this paper are available from http://www.rhad.de/