"People have been looking for monopoles in cosmic rays and particle accelerators — even Moon rocks," says Jonathan Morris, a researcher at the Helmholtz Centre for Materials and Energy in Berlin.
Now Morris and others have found the strongest evidence yet for magnetic monopoles, in small crystals about the size of an ear plug. When the crystals are chilled to near absolute zero, they seem to fill with tiny single points of north and south. The points are less than a nanometre apart, and cannot be measured directly. Nevertheless, Morris and other physicists believe they are there. They make their case in two papers published today in the journal Science, and other work published on the pre-print server arXiv.org.
Here are the references:
1. Kadowaki, H. et al. preprint at http://arXiv.org/abs/0908.3568v2 (2009).
2. Fennell, T. et al. Science advance online publication doi:10.1126/science.1177582 (2009).
3. Kadowaki, H. et al. preprint at http://arXiv.org/abs/0908.3568v2 (2009).
4. Bramwell, S. T. et al. preprint at http://arxiv.org/abs/0907.0956 (2009).
It remains to be seen whether these monopoles from the "spin ice" system can actually be considered as the actual monopoles that we've been looking for (don't think this is what the Standard Model had in mind).
Not surprisingly, such a fundamental discovery came, not from cosmic rays or particle accelerators, but from condensed matter physics! There should be no more question on whether CMP studies "fundamental" ideas or not. It should be patently clear already by now.
Edit: adding the link from ScienceNOW on the same topic.
Edit 10/15/09: S.T. Bramwell paper has now appeared in Nature. The exact reference is: S.T. Bramwell et al., Nature v.461, p.956 (2009).