I wrote: So it seems that under certain conditions, physicists are measuring > something vaguely like Mills's fractional hydrogen -- it might be that it > is Mills's fractional hydrogen, or it might be something entirely different. >
This is incorrect. The physicists are measuring *muonic* hydrogen and getting a different charge radius for the proton. So we're not dealing with Mills hydrogen or even something that looks like Mills hydrogen, since these have an electron and not a muon. If you extrapolate the charge radius from these experiments to the case of the normal proton-electron system, that is interesting. But what I don't understand yet is that the new charge radius is 0.04fm *smaller* than previously measured. In light of this, I'm not sure what is meant by the quotation going back to the paper that "The proton structure is important because an electron in an S [ground] state has a nonzero probability to be inside the proton." Eric
