[euyyn]

That's what we currently observe, yes. The particles of matter in the Standard Model are quarks (that join to form protons and neutrons among other things) and leptons (electrons, muons, taus, and neutrinos). The number of {quarks - antiquarks}, as well as that of {leptons - antileptons}, is conserved.

If you start with a proton and an electron, you have 3 quarks and 1 lepton, so whatever the interaction you have to end up with 3 quarks and 1 lepton (plus any number of quark-antiquark and lepton-antilepton pairs). E.g. for beta decay:

neutron (3 quarks) -> proton (3 quarks) + electron (lepton) + antineutrino (antilepton)