Of course. Sorry, I cited a bad example - electric charge is not conserved for electron-antiproton.
And if we look for a "truly convenient pair", we will find always restrictions based on charge conservation (any charge). Then, any particle-antiparticle annihilation is prohibited. Case closed...
Hello everybody and thank you for your comments!
In fact, my argumentation was essentially subjective. The intention was to consider new possibilities -to consider what was not previously considered, only by speculation. I mean that a colleague interpreted incorrectly my intention.
Regards to all
Just a question. A particle and a corresponding antiparticle (e.g. electron and positron) can annihilate by mutual interaction, producing energy (photons).
If the process of mutual annihilation occurs necessarily between particles and antiparticles (matter and antimatter), we would expect...