How does the spin of a pair of particles work if both particles are known to be chiral? generically if I sum the spins of two different (EDIT: spin 1/2, indeed ;-) particles I expect to get a triplet with S=1 [itex]\uparrow\uparrow[/itex], [itex]\uparrow\downarrow+\downarrow\uparrow[/itex], [itex]\downarrow\downarrow[/itex] and a S=0 singlet [itex]\uparrow\downarrow-\downarrow\uparrow[/itex], and in the case of identical particles only the singlet survives, isn't it? Now, that happens if both particles are non-identical but of the same chirality? Do we still have the four states? Only the [itex]\uparrow\uparrow[/itex] combination survives? or we have a "massless S=1" entity, with both [itex]\uparrow\uparrow[/itex], and [itex]\downarrow\downarrow[/itex]? And for different chiralities?