The neutron may be electrically neutral overall, but physicists had thought it was actually positively charged at its center with an offsetting negative charge at its outer edge. New results from three different particle accelerators suggest the neutron is even more complicated, with a negative charge both in its inner core and in its outer edge and with a positive charge sandwiched in between. The findings could improve understanding of the strong force, which binds atomic nuclei together, as well as the inner workings of stars. It might also have applications in nuclear energy and nuclear weapons. According to researcher Gerald Miller of the University of Washington, the neutron could prove even more complex as more data come in, as he describes in the September 14 Physical Review Letters.
This article was originally published with the title "Not So Neutral Neutron" in Scientific American 297, 6, 37 (December 2007)