The discussion revolves around the process of electron-positron annihilation, specifically focusing on what particles are emitted during this event. Participants explore the conditions under which different particles, such as photons and muon pairs, can be produced, and the conservation laws that apply to these processes.
Participants generally agree that the energy of the electron-positron pair influences the types of particles produced, but there is disagreement regarding the interpretation of charge conservation and how it applies to the particles created in annihilation.
The discussion includes assumptions about energy thresholds for particle production and the implications of conservation laws, which remain unresolved and are subject to interpretation.
zhermes said:It depends on the energy of the electron and positron. If they are low energy, the only things that can be created are photons; at higher energies there is some probability that muon-pairs will be produced, and at even higher energies even more massive particles can be produced.
As soon as the energy of the electron-positron pair exceeds the rest mass energy of a particle-anti-particle pair, I think there is some probability that it will be created.
There are numerous quantities you have to conserve; charge is one of them---which means that if a charged species is created (e.g. a muon, q = -e) another particle will also be created with the opposite charge (e.g. an antimuon, q = +e). Similarly, 'lepton number' needs to be conserved, energy, angular momentum (e.g. spin) etc etc.ravisastry said:If photons are created in annihilation, there won't be electric charge created in photons...but for Muon pairs, we have a positive and a negative muon. How can this be possible ?
zhermes said:There are numerous quantities you have to conserve; charge is one of them---which means that if a charged species is created (e.g. a muon, q = -e) another particle will also be created with the opposite charge (e.g. an antimuon, q = +e). Similarly, 'lepton number' needs to be conserved, energy, angular momentum (e.g. spin) etc etc.
Nope. It's experimentally very well established that only the total charge is conserved.ravisastry said:dont we have charge conservation for that particular charges ? like instead of sum total...how about total no of negative (or positive) charges should remain the same pre & post the event ?