On Sat, Aug 9, 2014 at 2:36 PM, Jones Beene <jone...@pacbell.net> wrote:
That is CODATA. Of course, it is no less accurate than any of the others. > Unfortunately, it is no more accurate either. How can it be when quarks > have variable mass? Variability in the mass of the quark does not prevent an accurate proton mass from being specified. What it does is places a bound on the numerical precision that an accurate proton mass value can have. In short, you say 938.2xx MeV, and CODATA (Wikipedia) says 938.272046(21) MeV. Both of these values is accurate to within your value, and the CODATA value may or may not be more accurate. (I have no opinion on whose value is the better one here.) Eric
