Wikipedia seems a bit imprecise on the common up and down quark
mass. See:
http://en.wikipedia.org/wiki/Quark
I wonder if the problem is the degree of nucleus excitation. The up
and down quark mass seem fairly straightforward to me (in my
simplistic Newtonian pea brained way of thinking.)
Mass of proton (2 up + 1 down) = 938.272 MeV/c^2
Mass of neutron (1 up 2 down) = 939.566 MeV/c^2
http://en.wikipedia.org/wiki/Neutron
http://en.wikipedia.org/wiki/Proton
So:
2 Mu + 1 Md = 938.272 MeV/c^2
1 Mu + 2 Md = 939.566 MeV/c^2
4 Mu + 2 Md = 1877.45 MeV/c^2 (2 x first equation)
=============================
-3 Mu + 0 Md = -937.884 MeV/c^2 (Subtract)
Mu = 312.628 MeV/c^2 (divide by 3)
Md = 938.272 - 2 Mu (from 1st equation)
Md = 313.471 MeV/c^2 (which checks with equations)
So, I get mass of the up quark 312.628 MeV/c^2 vs wiki 1.5 - 4.0 Mev/
c^2. I get mass of the down quark 313.471 MeV/c^2 vs wiki 4 - 8 Mev/
c^2. Something is way.... out of whack here???
The proton has maximum mass of 12 MeV/c^2???
Wiki notes the approximate chiral symmetry of quantum chromodynamics
gives the ratio:
Mu/Md = 0.56
I get:
Mu/Md = 0.56 = (312.628 MeV/c^2)/(313.471 MeV/c^2) = 0.997311
I would buy the notion that the wiki masses are rest masses and the
extra comes from relativistic mass, but the gamma should be the
roughly same for both quarks.
Anyone see a resolution to this seeming problem?
Regards,
Horace Heffner
