0 0.5 1 1.5 2 2.5 x 0 1 2 3 4 5 u b c s Upper Components,  $_{a}$( x ) 0 0.5 1 1.5 2 2.5 x 0 0.1 0.2 0.3 u b c s Lower Components, $_{b}$( x ) 31 FIG. 8: The lower component radial wave functions, − ψ$_{b}$ ( x ), for massless u and massive s , c , and b quarks. FIG. 7: The upper component radial wave functions, ψ$_{a}$ ( x ), for massless u and massive s , c , and b quarks.