Do protons and electrons lose energy due to radiation? Which one loses more energy, and why?
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2$\begingroup$ Are you talking about emission of light by atoms or free electrons and protons? $\endgroup$– Roger V.Commented Sep 28, 2020 at 11:00
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2 Answers
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The question probably could do with a little clarification as to what context and what you mean by 'due to radiation'?
I have assumed you mean 'Do protons and electrons decay via radiation to lose energy?' In which case:
-Electrons are fundamental, there is really nothing to decay to. They can lose energy if they have a mass-energy above their rest mass, but they will not decay.
-Protons are a bit of a longer answer. In practice, no, protons are the lightest of the baryons and therefore do not decay. They can interact with other particles, but don't decay of their own accord. There has been a lot of experimentation into this, and this conclusion is made with overwhelming significance (I can find the number for you, if you would like). That said, some beyond the standard model theories, hypothesise proton decay - though as yet, have not observed it. If it does exist, the half-life is 10^22 years times longer than the age of the universe.
Also, welcome to Physics SE
EDIT: Just to clarify this answer holds up for the situations of both a free particle and bound ones (though you can get beta+ decay in a bound state, this is not proton decay) and in the situation of accelerated particles
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$\begingroup$ Why not to add a paragraph for free particles? This would make the answer good independently of the OP meaning, which is not too clear. $\endgroup$ Commented Sep 28, 2020 at 12:30
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$\begingroup$ Is all of the above not true for free particles? $\endgroup$– EpidemeCommented Sep 28, 2020 at 12:39
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$\begingroup$ yes your are right. I meant free and accelerated. But op should really clarify also because as for the comment by Vadim. $\endgroup$ Commented Sep 28, 2020 at 14:13
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$\begingroup$ It's true for accelerated protons and electrons also (these are essentially quickly moving free particles), in that neither decay. You can collide them into things and get interactions, but this would not be agree. But yeh, totally agree, needs clarification. I'll add a note in the answer from your suggestion too. $\endgroup$– EpidemeCommented Sep 28, 2020 at 14:18
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1$\begingroup$ Still the op does not mention decay but if they radiate. They indeed radiates if accelerated, as well they indeed radiate when relaxes (of course is the system). Anyway sorry, I shouldn't have bother you but comment directly to the question. $\endgroup$ Commented Sep 28, 2020 at 16:25
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It depends on what state you're starting from, and what you mean by losing energy.
An atom can lose energy due to radiation, if the electrons are in an excited state. That energy doesn't come from the electrons or the protons, though. It comes from the electromagnetic fields within the atom.
Similarly, some nuclear processes (e.g. fusion and high-energy collisions) can put nuclei in an excited state which eventually decays by emitting gamma radiation. These nuclear isomers emit gamma radiation when they decay. Again the radiated energy is primarily from conversion of the nucleus's internal fields.
If you have a cloud of many particles, of any type, individual particles will vary in their kinetic energy. When those particles are charged, it is common for the kinetic energy to be radiated away as photons. The energy lost depends on the temperature. The detailed processes is used in particle accelerators and atomic-physics experiments to manage the sample temperature. (See Laser cooling, Doppler cooling, or other application-specific topics.) The energy is coming from the individual particles in this case, but it's typically a small amount relative to their rest energy, so mass changes are negligible. Both protons and electrons radiate by similar processes, and the temperature-to-mass ratio is important, but there's not much fundamental difference between them otherwise.
