# How does one experimentally determine chirality, helicity, spin and angular momentum?

If I've got an instance of a fundamental particle, how can I separate out the measurements of these three concepts?

(I think) I understand the theory behind them, and why the particles in the standard model are predicted to have the values they do. However, the process of validation of these numbers eludes me. How have they been historically measured?

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People often confuse helicity and chirality they are only the same in the case of massless particles. This is also the reason why we know that (at least interacting) neutrinos are always left-handed (the famous $$SU(2)_L$$ ), at least if we assume that neutrinos are massless (which is almost the case, but not strictly).
 This answer is fine +1, but the $SU(2)_L$ is before Higgs mechanism, where the neutrino is perfectly massless as well as the electron. – Ron Maimon Apr 26 '12 at 4:54 one should also add that for decaying particles angular distributions of the decay products in the center of mass system can determine spin. – anna v Apr 14 at 10:50