Energy: in electron volts (eV). The energy gained by an electron crossing a potential of one volt. 1 eV = 1.6 x 10^(-19) joules. A MeV is a million electron volts, and a GeV is a billion electron volts.
Mass: in GeV/c2
(a billion electron volts divided by the speed of
light squared. Mass is measured in terms of energy because mass IS just a
form of energy -- remember
.) 1 GeV is
about the amount of energy needed to create a
proton (the mass of a proton is
0.938 GeV/c2 = 1.67 x 10 ^ (-27) kg.)
Spin: the internal angular momentum of a particle,
in units of 
.
= h /
(2
) =
6.58 x 10^(-25) GeV s = 1.05 x 10^(-34) J s.
Electric Charge: in terms of the proton's charge (+1), or in SI units, 1.60 x 10^(-19) coulombs.