Can muonic atoms exist? Would it be possible in the standard model to have atom like systems in which muons (or tauons) take the place of electrons? Why don't we see more of them?
For instance it could be related to some mechanism leptogenesys, but I don't know much about this subject..
How the difference between muonic and electronic atoms could affect astronomical data?
Correct me if I am wrong, but I guess there is no analogue for protons and neutrons, especially since protons have very long life.
 A: Absolutely they can exist. In fact, physicists often creat muonic hydrogen to study things like the structure/size of the proton with more accuracy.
The reason we don't see muonic/tauonic atoms in nature is that these particles decay very quickly, whereas the electron, being the lightest of the three generations of leptons, has an essentially infinite lifetime.
A: Muonic atoms can be made from one antimuon and one electron. The antimatter version of this antimuonium is where one muon is orbited by a positron. The decay product goes like this:
Now the electron orbits the W+ boson and normally the W+ would decay into a positron and neutrino. However electron and W+ react way before that. This results in electron neutrino. Th end products are anti-muon neutrino and electron neutrino
$\mathrmμ^+=\bar{v_μ}+W^+$
$\mathrm W^++e^-={v_e}$
Muonium decays to muon neutrino and electron antineutrino in little over 2.2 microseconds(the life time of muons).
For antimuonium decay here is the equation:
$\mathrmμ^-=\nu_μ+W^-$
$\mathrm W^-+e^+=\bar{v_e}$
Here there is a muon neutrino and an antielectron neutrino.
A: Muons and tauons are very heavy and unstable particles. They generally decay into electron that is why they are rarely found in nature.
