The BxDecay0 C++ library provides a set of classes and functions for the random generation of simulated nuclear decays. It consists in a C++ port of he original Decay0 Fortran program (also known as GENBB in some other context) written and maintained by Volodymyr Tretyak (KINR). Decay0 was created to address the Monte Carlo generation of nuclear decays in the context of double beta decay and dark matter experimental research.

BxDecay0 aims to be used by any C++ simulation program that needs to generate the kinematics of primary particles emitted from specific nuclear decays (example: input for a Geant4 based Monte Carlo simulation program). It can be easily interfaced with the HepMC event/particle model or any other client application.

BxDecay0 provides an extension library which implements an interface for Geant4 (through a PrimaryGeneratorAction class and its associated messenger).