Exotic particle packs a foursome of quarks

Tetraquarks could help physicists understand the universe’s first generations of matter

The rediscovery of an exotic particle provides the best evidence yet that quartets of quarks exist in a universe dominated by two- and three-quark matter.

By validating the particle’s existence, says lead author Tomasz Skwarnicki, a physicist at Syracuse University in New York, “we are automatically proving that four-quark states exist.”