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CainIsmene t1_jc0bw4s wrote

No. Antineutrons don't exist in the proverbial vacuum, they're comprised of more fundamental particles called quarks, in this case antiquarks.

Antineutrons are made of two antidown quarks and one antiup quark.

A proton is comprised of two up quarks, and a down quark.

So, if you stick an antineutron in contact with say two regular protons they'll annihlate and, if you're lucky, create a Δ++ baryon that'll decay into a proton and a positively charged pion that'll then decay into a muon and muon neutrino, and then that muon will decay into an electron, an electron neutrino, and an antimuon neutrino that'll annihilate with the muon neutrino that was made when the pion decayed and leave you, ultimately, with a hydrogen atom.

subatomic physics is weird my man

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damondefault t1_jc1g5it wrote

Ok but did you remember that reaction chain off the top of your head or did you have to look some of it up?

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sejanus21 t1_jc1p09h wrote

my question is are you guys talking about real observable things or are these words you all utter theoretically? like string theory.

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Sharlinator t1_jc1ujz3 wrote

Well, theory predicts these reactions and experiments eg. with particle colliders have shown that the predictions match exactly what actually happens, to a high precision.

Indeed the theory (the so-called standard model of particle physics) is so successful that phycisists are frustrated because despite its success, it’s also incomplete, but not even the LHC has found even a hint of any new physics beyond the standard model.

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bildramer t1_jc1q83k wrote

You can build an actual machine to detect muons from space (more precisely: from the upper atmosphere), for example. The particles are all very short-lived, but they do exist.

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mesouschrist t1_jc20scn wrote

I work on an experiment that traps antiprotons and we detect their presence by having them hit the wall of the trap (made of, obviously, normal matter) and we detect the charged pions. While these aren't antineutrons, it's the same exact concept. So yes this process is definitely observable.

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Doc_Lewis t1_jc2ju74 wrote

For a real world application, see PET scans. Positron emission tomography, a common imaging technique in healthcare, relies upon certain radioactive isotopes that undergo beta decay. That is to say, an up quark in a proton flips to down, and turns the proton into a neutron, and ejects a positron (antimatter electron). When the positron meets an electron, they annihilate and release gamma rays, which are detected.

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Shishire t1_jc0jfun wrote

Shouldn't that also leave you with an electron neutrino? Or is there another interaction there that consumes that?

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mesouschrist t1_jc21af1 wrote

One small caveat - neutrino/antineutrino "annihilations" have never been detected, and probably almost never happen in nature. There is a whole branch of experimental physics with 10s of large scale experiments looking for this process (neutrinoless double beta decay experiments). And there are scores of theoretical physicists developing theories in which neutrinos don't have antiparticles (Majorana neutrinos). People doubt neutrinos are majorana particles only because that would be odd - since all the other fermions are not majorana in the known universe.

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kyrsjo t1_jc1b75z wrote

Seems unlikely that the muon neutrinos will interact, but yeah.

And then the "antimuon neutrino" isn't actually a real eigenstate, so over time it will oscillate to other anti-neutrinos...

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