Are protons magnetic?

Kalrag

Alright, this one is really bugging me. Are protons magnetic. Are they attracted to a magnet or can the be controlled by a magnet?

cragar

They have a Magnetic moment and so do neutrons .

Idoubt

yes they can be controlled magnetically, that's how particle accelerators work.

Kalrag

So is that also true for neutrons. That they can be controlled by magnets?

DaleSpam

That is also how magnetic resonance imaging works.

cragar

Yes but their B field is very weak.

Sakha

Just to clear a point: a magnetic field will not do work on the proton. It will accelerate the proton in a circular way, just changing the direction but not the magnitude.

JDługosz

Individual protons are magnetic in the same sense as individual electrons! They are both charged spin-1/2 particles.

granpa

http://en.wikipedia.org/wiki/G-factor

electron fudge factor

proton and neutron fudge factor

muon fudge factor

JDługosz

Other than being more massive, can you explain what the differences are? How does this affect its motion, in contrast to (just) its mass and charge?

granpa

We would expect magnetic moment and angular momentum to always be proportional to each other.
They arent.
Hence the fudge factors.

K^2

What you said is true for CONSTANT magnetic field. A gradient in the field can accelerate a magnetic moment.

QuantumPion

This doesn't sound right to me. Particle accelerators use magnetic fields to curve the path of protons but this is due to the proton's electric charge moving through an external magnetic field, not the proton's magnetic moment.