Sharper view of matter
In a breakthrough that could one day yield important clues about the nature of matter itself, a team of Harvard scientists has measured the magnetic charge of single particles of matter and antimatter with unprecedented precision. As described in a March 25 paper in Physical Review Letters, the team — led by Gerald Gabrielse, the George Vasmer Leverett Professor of Physics, and including postdoctoral fellows Stephan Ettenauer and Eric Tardiff and graduate students Jack DiSciacca, Mason Marshall, Kathryn Marable, and Rita Kalra — was able to capture individual protons and antiprotons in a “trap” created by electric and magnetic fields. By tracking the oscillations of each particle, the team was able to measure the magnetism of a proton 1,000 times more accurately than any proton had been measured before. Similar tests with antiprotons produced a 680-fold increase in accuracy in the size of the magnet in an antiproton. “That is a spectacular...