# Builds an anti-nucleus composed of anti-proton and anti-neutron

1. Nov 10, 2008

### JustinLevy

I thought that was a neat idea. However, the mass is greater and thus the equivalent "bohr radius" would be much smaller. Maybe the two effects cancel (or maybe this decays even faster than positronium). I'm not sure how to calculate the decay rate since the particles are composite, have color charge, and is more energic with more decay products possible.

I'm curious now. Anyone know which would decay faster? Is there some kind of shortcut / handwavy back of the envelope method we can use here?

2. Nov 10, 2008

Staff Emeritus
Re: Nucleitronium?

The Bohr radius of protonium is ~10^-3 of hydrogen, or about 100 proton radii. I'd start with the wavefunction overlap, which is going to tell you that the antiproton spends ~1% of its time inside the proton, so you get something like 100 orbits before decay. Each orbit will take ~(2pi)r/c time, or maybe 10^-21 s. So I would guess the ballpark is 10^-19 seconds.