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/c2
(remember E = mc2),
where 1 GeV = 109 eV = 1.60 x 10-10 joule.
The mass of the proton is 0.938
GeV/c2 = 1.67 x 10-27 kg.