Strong force?

Question

im no stranger to the strong force. i get it, gluons act as mediator particles between quarks, and hold nucleons and the nucleus together.

but humor me for a second. take the neutron for example. neutral charge, it would seem as if it doesnt electromagnetically bond with anything. BUT it is polar. it has a side with a -2/3 charge and a side with a +2/3 charge, sort of like a water molecule. since its polar, wouldnt it be possible for the positive side of a neutron to bond with the negative size of another, and therefore hold the nucleus of an atom together?

idk, maybe im just thinking out loud here. possible?

Answer 1

The neutron does not in fact have a measurable electric dipole moment. This is primarily because of the fact that the neutron is not really a particle consisting of three quarks - that is just a classical view - the quantum-mechanical view treats them as wave-packets obtained by summing the contributions of smaller wave-packets - quarks, anti-quarks, and gluons - which average out to give what appears to be three "real" quarks and a large number of transient "virtual" quark-antiquark pairs and gluons.

The physics involved is more complicated than either you or I have the knowledge/experience to understand, but it can be shown that if the strong nuclear force has CP symmetry then the neutron should be electrically neutral. Otherwise, the neutron will have an electric dipole moment, and the more the force violates CP, the greater this dipole moment.

CP symmetry means that if all particles' charges are flipped (C for charge), and the system is converted to its mirror image (P for parity), then the system will continue evolving in the exact same way as it would if this change had not occured.

In the current theories of physics, it is not necessary that the strong nuclear force preserves this CP symmetry. Indeed, there is a parameter, denoted by capital theta with a bar over it, which is supposed a fundamental constant representing the extent to which the strong nuclear force violates CP symmetry. It would seem that this constant is very close to zero, which effectively makes a neutron's charge uniform.

See the article

http://en.wikipedia.org/wiki/Axion

for interest-reading and more information.

P. S. I like your About section. I can't tell you how much I agree.