D0C : A code to calculate scalar one-loop four-point integrals with complex masses

TL;DR

This paper introduces a Fortran code for calculating scalar one-loop four-point integrals with complex masses, applicable to collider physics, addressing numerical challenges and special cases.

Contribution

It provides a new computational tool based on 't Hooft and Veltman's method, covering all physical collider processes with complex masses and special cases.

Findings

Code effectively handles complex masses and special cases.

Addresses numerical evaluation issues and Landau singularities.

Applicable to all collider-relevant external momenta conditions.

Abstract

We present a new Fortran code to calculate the scalar one-loop four-point integral with complex internal masses, based on the method of 't Hooft and Veltman. The code is applicable when the external momenta fulfill a certain physical condition. In particular it holds if one of the external momenta or a sum of them is timelike or lightlike and therefore covers all physical processes at colliders. All the special cases related to massless external particles are treated separately. Some technical issues related to numerical evaluation and Landau singularities are discussed.