There are several quantum numbers used to explain the energy states of particles. For example, no two electrons can have the same four quantum numbers in an atom. Now, I was wondering if the following "guess" I had about antimatter particles is plausible: a quantum number is added to "describe" the states of an electron and a positron, a quantum number that would have a two-valuedness with the purpose of "describing" one more degree of freedom, where, for example, an electron and a positron can't have the same set of quantum numbers and as a result these particles are observed as a matter/antimatter pair. Perhaps my "guess" is none other that the lepton number and I am overthinking it? However, do you agree if adding a completely new quantum number (to explain why the imbalance in matter and antimatter) is plausible?