# Does strong force increase or decrease with aligned spins?

• I
The deuterium exists only with the proton and neutron of aligned spin, which suggests that the residual strong force is greated with aligned spins, i.e. the binding energy is greater if the spins are aligned.

On the other hand the mass of ##\Delta^{+}## is greater than the mass of proton ##p##, even if they have the same quarks, since ##\Delta^+## has aligned spins of quarks. So it seems that here the binding energy decreases if spin are aligned (greater mass -> smaller binding energy).

Another fact in this sense is that in Weizsäcker formula the pairing term makes the binding energy of nucleus to increase if the spins are paired (i.e. opposite). (here the strong force is again residual as in deuterium)

So how are these two consistent? Does the strong force increase with aligned spins?

crick