Can an atomic nucleus contain both particles and antiparticles?

Question

Is it theoretically possible to make a "deuterium" atom containing a proton and an antineutron in its nucleus?

Would the strong nuclear force cause attraction between a proton and an antineutron?

Would such a nucleus be stable, or would the proton somehow annihilate the antineutron when close enough?

Wikipedia has some info on annihilation reactions between nucleons & antinucleons, as I mention in this answer. — PM 2Ring, Jan 29 '19 at 14:03

score 14 · Accepted Answer · answered Jan 29 '19 at 13:44

14

An antineutron ($\bar{u}\bar{d}\bar{d}$) is made up of antiquarks and these will annihilate with the quarks in the proton ($uud$).

Such a nucleus is therefore unstable.

answered Jan 29 '19 at 13:44

rnva

11

That does look like the most likely fate of such a system. The remaining $\bar d$ and $u$ quarks would then likely form a $\pi^+$ pion, which would eventually decay to an antimuon and then a positron. – Emilio Pisanty Jan 29 '19 at 13:50
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N.B. from the links in the duplicates, it appears that there are short-lived $p\bar{n}$ and $\bar{p}n$ bound states, so the answer to "Would the strong force cause attraction ..." is yes. – zwol Jan 29 '19 at 18:17

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