Physicists have known since the turn of the past century that protons lie at the heart of all ordinary matter. But this elementary component of nature has kept from scientists some secrets about its inner workings.
Researchers taking one of the closest looks yet into the intact proton have found an unexpectedly complex interior electromagnetic environment. The new findings come as a shock to nuclear and particle physicists who have considered this aspect of the proton to be well understood for more than a half century.
The results "have drastic consequences for the way we understand what the proton is made of," says Charles F. Perdrisat of the College of William and Mary in Williamsburg, Va., one of the experiment's leaders.