# Neutrino and electromagnetic forces

I learned from Wikipedia that neutrinos "are not affected by the electromagnetic forces". How was this identified experimentally?

-

Experimentally it has been found that neutrinos travel in a straight line through matter, unless they interact directly with nuclei on the way into a spate of particles. Their path is not affected by the magnetic field of a bubble chamber for example. (The OPERA neutrinos travel kilometers in a straight line unaffected by the magnetic field of the earth).

They leave no ionization trace in matter, as the other particles in the bubble chamber event.

Thus they are not charged.

They can interact electromagnetically with other charged particles through higher order Feynman diagrams, but as this would require a first weak vertex, the probability of interaction electromagnetically is very low and can be ignored to all practical purposes.

-
Thank you very much. But correct me if I'm wrong: the bubble chamber can only detect electrically charged particles. I'm testing the conjecture that neutrinos bear magnetic charge instead of electric charge. Are there any other experimental evidences other than bubble chamber experiments? –  Murod Abdukhakimov Mar 24 '12 at 8:53
all neutrino experiments. bubble chamber are the ones that are visual. There is no magnetic charge, i.e. they are not monopoles. If they were they would also ionize like the electric charge. It is one of the reasons we know there are no magnetic monopoles in the particle interactions. It would be an ionizing track with a funny behavior to the magnetic field (attracted up or down with respect to the plane of B, rather than a circular path). –  anna v Mar 24 '12 at 9:32
@anna v: Just to add for people who don't know this, an interaction like that would involve several factors of the weak coupling constant and would be a very small interaction compared to something like an electron scattering off of a $\vec E$ field. –  Jerry Schirmer Mar 23 '12 at 20:49