Relativistic Voigt profile for unstable particles in high energy physics

The Voigt profile is one of the most used special function in optical spectroscopy. In particle physics a version of this profile which originates from relativistic Breit-Wigner resonance distribution often appears, however, in the literature there is no strict derivation of its properties. The purpose of this paper is to define properly relativistic Voigt profile and describe it along the same way as their standard nonrelativistic counterparts.