sci-physics@gentoo.org Gentoo Physics Project HepPDT contains the fixed data about each particle type. In other words, it contains the data that can be found in the Review of Particle Properties. This data is conceptually split into particle information (e.g. mass) and decay information. HepPDT provides a simple set of particle data classes. Particle ID translation methods are in a separate HepPID library, which is distributed as part of HepPDT.