# OneLOop: For the evaluation of one-loop scalar functions

## Description

Abstract OneLOop is a program to evaluate the one-loop scalar 1-point, 2-point, 3-point and 4-point functions, for all kinematical configurations relevant for collider-physics, and for any non-positive imaginary parts of the internal squared masses. It deals with all UV and IR divergences within dimensional regularization. Furthermore, it provides routines to evaluate these functions using straightforward numerical integration. Title of program: OneLOop Catalogue Id: AEJO_v1_0 Nature of problem In order to reach next-to-leading order precision in the calculation of cross sections of hard scattering processes, one-loop amplitudes have to be evaluated. This is done by expressing them as linear combination of one-loop scalar functions. In a concrete calculation, these functions eventually have to be evaluated. If the scattering process involves unstable particles, consistency requires the evaluation of these functions with complex internal masses. Versions of this program held in the CPC repository in Mendeley Data AEJO_v1_0; OneLOop; 10.1016/j.cpc.2011.06.011 This program has been imported from the CPC Program Library held at Queen's University Belfast (1969-2018)