According to physicists of the Beijing-based BESIII experiment, their discovery of a new subatomic particle named Zc (4020) hints at a novel class of four-quark objects. This image shows the four-quark structure of Zc (3900). Image credit: APS / Alan Stonebraker. Quarks are the fundamental building blocks of nature. They combine to form protons, neutrons and hundreds of other particles called hadrons. Until recently hadrons were believed to have only...
