Large Hadron Collider Discovers 4-Quark Exotic Particle, Challenging Physics

Using the Large Hadron Collider beauty (LHCb) Collaboration, scientists have confirmed the existence of exotic hadrons, a type of matter that cannot be classified within the traditional quark model. The new findings are a breakthrough for physics.

Quarks are hard, point-like objects that can be found within the nucleus of an atom. When these particles combine in threes, they form compound particles known as baryons. Protons are actually best known as baryons. Yet sometimes, these quarks interact with anti-particles, which have the same but opposite charges. That causes then to form mesons.

"We've confirmed the unambiguous observation of a very exotic state-something that looks like a particle composed of two quarks and two anti-quarks," said Tomasz Skwarnicki, one of the resrearchers, in a news release. "The discovery certainly doesn't fit the traditional quark model. It may give us a new way of looking at strong-interaction physics."

Mesons, baryons and other kinds of particles that take part in strong interactions are called hadrons. Yet in 2007, researchers discovered an exotic particle which appeared to have two quarks and two anti-quarks. This particular particle, called Z(4430), changed their understanding of hadrons. At the time, though, researchers weren't sure whether the particle actually existed. Now, a new experiment has proven that it does.

The researchers analyzed tens of thousands of meson decays, selected from trillions of collisions in the Large Hadron Collider. This gave researchers the data they needed to prove the particle's existence.

"This experiment is the clincher, showing that particles made up of two quarks and two anti-quarks actually exist," said Skwarnicki in a news release. "There used to be less-clear evidence for the existence of such a particle, with one experiment being questioned by another. Now we know this is an observed structure, instead of some reflection or special feature of the data."

The findings provide evidence for the existence of the particle. This, in turn, could help inform future experiments in physics.