4 ms·

Arguments about matter-antimatter balance are actually per quantum field. Electrons can't, in any sense, be "antimatter". That's because there antimatter as a

Arguments about matter-antimatter balance are actually per quantum field. Electrons can't, in any sense, be "antimatter". That's because there antimatter as a concept only applies to a particle's relationship to its antiparticle -- it's not a feature of a single type of particle, only of two types of particle. Which must be variant excitations of the same quantum field. That's almost irrelevant, however. The big bang should have created roughly equal amounts of matter and antimatter for each quantum field; an excess of protons cannot be balanced by deficit of positrons, as I believe you were suggesting. Protons and positrons do not annihilate, nor would protons and electrons for that matter. Only protons and anti-protons, or electrons and positrons, have that reaction. (Though, aside: Protons are composite particles. None of the composites are electrons, though, so this still applies.)

ben_w 5y ago
This reminds me of a question that popped into my mind earlier this year. Forewarning: I’m not a professional physicist. If the Big Bang didn’t create an equal quantity of matter and antimatter, and given that antimatter is still being produced by various cosmological sources and at a lower rate for proton-antiproton pairs than for electron-positron pairs, would that imply that the universe has a non-zero net electric charge which is still changing over time? And if so, what would a universe with a significant non-zero electric charge look like? And if not, because Noether, could the combination of e.g. antiprotons and positrons into anti-neutrons turn out to be stable and one possible candidate for dark matter? (Full blogpost: https://kitsunesoftware.wordpress.com/2021/02/09/baryon-asymmetry/ https://kitsunesoftware.wordpress.com/2021/02/09/baryon-asym...)
- adrian_b 5y ago
  As far as we know, during Big Bang, after the matter had cooled enough for heavier particles to decay but before cooling enough to allow the formation of nuclei and atoms, there were equal numbers of protons, neutrons and net electrons (i.e. electrons - positrons), so the electric charge of the universe was zero. All the events that happened after that, e.g. the decay of a part of the neutrons into protons and electrons, the annihilation of positrons with electrons and various generations and annihilations of particle/anti-particle pairs, have not changed the total electric charge, so it has remained zero. The electric forces are extremely strong and they ensure that matter is on average electrically neutral, so the only long-distance forces are magnetic and gravitational. Any region with electric charge would generate strong electric fields with various obvious effects.
  - ben_w 5y ago
    The observed bias of matter in favour of antimatter is a problem for the claim that particle-antiparticle pairs should have only ever been created or destroyed in matching pairs. To rephrase my two questions about that observation: 1) What if the observed baryon asymmetry is an illusion because anti-neutrons are stable, unlike their mater counterparts? Would that explain anything? 2) If baryon asymmetry is real and not an illusion, what else should we expect to see? > The electric forces are extremely strong and they ensure that matter is on average electrically neutral, so the only long-distance forces are magnetic and gravitational. Which is why my question is specifically with regard to the observed baryon asymmetry as that might (in the case of question 2) mean the charges can’t be balanced. > Any region with electric charge would generate strong electric fields with various obvious effects. If the charge was distributed isotropically rather than in a limited region?

ben_w 5y ago

This reminds me of a question that popped into my mind earlier this year. Forewarning: I’m not a professional physicist. If the Big Bang didn’t create an equal quantity of matter and antimatter, and given that antimatter is still being produced by various cosmological sources and at a lower rate for proton-antiproton pairs than for electron-positron pairs, would that imply that the universe has a non-zero net electric charge which is still changing over time? And if so, what would a universe with a significant non-zero electric charge look like? And if not, because Noether, could the combination of e.g. antiprotons and positrons into anti-neutrons turn out to be stable and one possible candidate for dark matter? (Full blogpost: https://kitsunesoftware.wordpress.com/2021/02/09/baryon-asymmetry/ https://kitsunesoftware.wordpress.com/2021/02/09/baryon-asym...)

adrian_b 5y ago
As far as we know, during Big Bang, after the matter had cooled enough for heavier particles to decay but before cooling enough to allow the formation of nuclei and atoms, there were equal numbers of protons, neutrons and net electrons (i.e. electrons - positrons), so the electric charge of the universe was zero. All the events that happened after that, e.g. the decay of a part of the neutrons into protons and electrons, the annihilation of positrons with electrons and various generations and annihilations of particle/anti-particle pairs, have not changed the total electric charge, so it has remained zero. The electric forces are extremely strong and they ensure that matter is on average electrically neutral, so the only long-distance forces are magnetic and gravitational. Any region with electric charge would generate strong electric fields with various obvious effects.
- ben_w 5y ago
  The observed bias of matter in favour of antimatter is a problem for the claim that particle-antiparticle pairs should have only ever been created or destroyed in matching pairs. To rephrase my two questions about that observation: 1) What if the observed baryon asymmetry is an illusion because anti-neutrons are stable, unlike their mater counterparts? Would that explain anything? 2) If baryon asymmetry is real and not an illusion, what else should we expect to see? > The electric forces are extremely strong and they ensure that matter is on average electrically neutral, so the only long-distance forces are magnetic and gravitational. Which is why my question is specifically with regard to the observed baryon asymmetry as that might (in the case of question 2) mean the charges can’t be balanced. > Any region with electric charge would generate strong electric fields with various obvious effects. If the charge was distributed isotropically rather than in a limited region?