Revised August 2023 by A. Buckley, F. Krauss, S. Navas, P. Richardson.

The Particle Data Group maintains this numbering scheme in cooperation with Monte Carlo authors and the StdHep Monte Carlo Standardization project at Fermilab, as part of a system to facilitate translation between different Monte Carlo event generators and detector simulators. The StdHep lists contain a few specialized codes beginning with 99 which are needed for particular event generators, but which are not included in the list of PDG particle numbers.

Comments should be sent to: D. Robinson