Resolves when and based on what? Last available version of the Review of Particle Physics at the time of market closing? If it's close enough does it resolve to PROB based on a Gaussian (e.g. to 16% if it's 882.724 ± 0.001)? Or does it stay open until it's either above or below at 5 sigma?

@ArmandodiMatteo Stays open until we know the answer to the question with confidence.

@IsaacKing Weird-ass stuff such as a neutron-mirror neutron oscillation wouldn't count as a "decay" — only decays into several lighter particles count, right?

@ArmandodiMatteo Hmm, good question. I think the most natural answer is that if mirror neutrons can oscillate back to a regular neutron then that doesn't count as a decay, but if it's stuck as a mirror neutron permanently then that does count as a decay. (And in the former case, it counts as a decay as soon as either the regular neutron or its mirror form decays further.)