with the derivative understood to be acting towards the left. The conjugate spinors are then u ¯ ¯ ( s ) ( p → → ) = u ¯ ¯ ( s ) ( 0 → → ) p / + m 2 m ( E + m ) and v ¯ ¯ ( s ) ( p → → ) = v ¯ ¯ ( s ) ( 0 → → ) − − p / + m 2 m ( E + m )