You searched for: “helicity
The projection of a particle's spin vector in the direction of its momentum vector, being positive if it points in the same direction, and negative if it points in the opposite direction.

Helicity is in effect the handedness, or chirality, of the spin of a particle.

This entry is located in the following units: helico-, helic-, helici-, heli-, helix- (page 1) -ity (page 9)