February 21, 2013 • Article by Caroline Hanna
This picture depicts the long-range spin-spin interaction (blue wavy lines) in which the spin-sensitive detector on Earth’s surface interacts with geoelectrons (red dots) deep in Earth’s mantle. The arrows on the geoelectrons indicate their spin orientations, opposite that of Earth’s magnetic field lines (white arcs). Illustration: Marc Airhart (University of Texas at Austin) and Steve Jacobsen (Northwestern University).
In a breakthrough for the field of particle physics, Larry Hunter, the Stone Professor of Natural Sciences (Physics), and colleagues at Amherst and The University of Texas at Austin have established new limits on what scientists call “long-range spin-spin interactions” between atomic particles. These interactions have been proposed by theoretical physicists but have not yet been seen. Their observation would constitute the discovery of a “fifth force of nature” (in addition to the four known fundamental forces: gravity, weak, strong and electromagnetic) and would suggest the existence of new particles, beyond those presently described by the Standard Model of particle physics.