Spin is the intrinsic angular momentum of particles.
Spin is given in units of
h-bar, which is the quantum unit of angular momentum, where
hbar = h/2pi = 6.58 x 10^{-25} GeV s = 1.05 x 10^{-34} J s.

Electric charges are given in units of the proton's charge.
In SI units the electric charge of the proton is 1.60 x 10^{-19} coulombs.

The energy unit of particle physics is the electron volt (eV),
the energy gained by one electron in
crossing a potential difference of one volt.
Masses are given in GeV/*c*^{2}
(remember *E = mc ^{2}*),
where 1 GeV = 10