Chirality, helicity as a projection of its spin vector .. that becomes a kind of 'virtual spin'?

I often confuse them: but the particles 'spin' on the right or left, or is the projection of .. what? Left or right is a simbolic term to describe a particle degrees of freedom?

  • $\begingroup$ Helicity is projection of spin on the momentum axis. Chirality is transformation rule with respect to Lorentz group. For masless particles these two properties coincide. $\endgroup$ – Blazej Jul 29 '16 at 13:59