# Can an atomic nucleus contain both particles and antiparticles? [duplicate]

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. Jan 29, 2019 at 14:03

An antineutron ($$\bar{u}\bar{d}\bar{d}$$) is made up of antiquarks and these will annihilate with the quarks in the proton ($$uud$$).
• 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. Jan 29, 2019 at 13:50
• 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.