The handedness of an electron refers to the orientation of its spin relative to its direction of motion. The electrons are all the same but the state they are e

The handedness of an electron refers to the orientation of its spin relative to its direction of motion. The electrons are all the same but the state they are emitted into is different. The weak nuclear force breaks chiral symmetry, so in beta decays--which are governed by the weak force--you tend to get neutrinos with their spin aligned with their direction of motion and electrons with their spin anti-aligned with their direction of motion, where "aligned" means if your right thumb is pointed in the direction of motion, the curling of your fingers gives the sense of rotation associated with the spin and "anti-aligned" is the same except that it's your left thumb pointing along the direction of motion. In a system with strict chiral symmetry the two spins would always be opposed (which is required because angular momentum is conserved) but there would be no preference relative to each particle's direction of motion.