The 27-kilometer (16.8-mile) LHC at CERN is the machine that found the Higgs boson particle, which, along with its associated energy field, is thought to be crucial to the formation of the universe after the Big Bang 13, 7 billion years. Now scientists at CERN say they have spotted a new kind of ‘pentaquark’ and the first pair of ‘tetraquarks’, adding three members to the list of new hadrons found at the LHC. They will help physicists better understand how quarks bind together into complex particles. Quarks are elementary particles that usually combine in groups of twos and threes to form hadrons, like the protons and neutrons that make up atomic nuclei. More rarely, however, they can also combine into four-quark and five-quark particles, or four-quark and five-quark particles. “The more analyzes we do, the more exotic hadron species we find,” physicist Niels Tuning said in a statement. “We are witnessing a period of discovery similar to the 1950s, when a ‘particle zoo’ of hadrons began to be discovered and eventually led to the quark model of conventional hadrons in the 1960s. We are creating ‘particle zoo 2.0.’
