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Is an electron more stable than a proton/neutron under extreme temperature/pressure conditions, like several 100 millions K?

Qmechanic
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Christian Speth
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    To answer you have to provide also the baryon number, the lepton number and total charge of your system (plus the temperature). In this way it could be possible to calculate the full thermal and beta equilibrium (so beta reactions are in statistical balance). For vacuum the existing answer is correct. However "stability" 99% of times is a vacuum property, intrinsic to the particle, so I would accept that answer or clarify what you mean by "stability". – Quillo Mar 19 '23 at 10:48
  • Related: https://physics.stackexchange.com/q/538672/226902 and https://physics.stackexchange.com/q/721203/226902 – Quillo Mar 19 '23 at 11:28

1 Answers1

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Is an electron more stable than a proton/neutron?

Yes. An electron has no internal structure, and is the lightest fundamental particle with a non-zero electric charge. Therefore it cannot spontaneously decay into a lighter particle without violating charge conservation. So any transformation of an electron must either involve adding a large amount of energy to it, or an interaction with another particle (e.g. electron capture or electron-positron annihilation).

Protons and neutrons, however, are made up of quarks. Outside of a nucleus, a free neutron spontaneously decays into a proton, an electron and a neutrino, with a half-life of about 14 minutes. A free proton does not spontaneously decay in a similar way (as far as we know) because its mass is slightly less than the mass of a neutron. However, both neutrons and protons inside unstable nuclei can spontaneously decay via beta decay.

gandalf61
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    That's the vacuum answer, but the OP asked about temperature/pressure, so collisions matter. That makes it more complicated, and requires a clearer idea of what "stable" is intended to mean. – John Doty Mar 18 '23 at 13:11
  • When a neutron star collapses into a black hole, is it concievable that the neutrons on the surface, now in free fall, will liberate a number of electrons, then? These could subsequently form an electron cloud surrounding the formed black hole. – Christian Speth Mar 18 '23 at 15:34
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    correction: an electron has no known internal structure. however, since an electron has mass, it theoretically should have some sort of internal structure and should decay on a long enough time scale. google preons for further reading. – teldon james turner Mar 18 '23 at 17:22
  • Well everything ever written about Physics is only what we "know". For electrons, their possible rate of decay is slightly longer than the 14 minutes mentioned in the answer... https://physicsworld.com/a/electron-lifetime-is-at-least-66000-yottayears/ @jamesturner – AnoE Mar 18 '23 at 23:11
  • Nobody seems to have observed at proton or an electron decay, so why is it believed that any particle with mass in principle is instable? And what about quarks? – Christian Speth Mar 19 '23 at 07:41
  • @ChristianSpeth mass is just a measure of total energy and energy is the interaction of massless particles so particles with mass must have internal interactions. particle interactions are probabilistic with a non-zero chance of very bizarre things happening. so usually when 2 protons interact inside a nucleus they stay bound, but very very very rarely they don't and that's called decay. neutrinos for example had no known internal interactions and so were believed to be massless, but we eventually proved otherwise by solving the solar neutrino problem – teldon james turner Mar 20 '23 at 12:59