PostedJuly 6, 2022, 5:51 PM
Ten years after the discovery of the Higgs boson and barely restarted, the LHC accelerator has added three exotic objects to its particle zoo.
The new pentaquark, a pair of weakly bound classical hadrons in a molecule-like structure, is composed of a c quark and a c antiquark, and an up quark, a d quark and of an s quark.
CERN
It didn’t drag. CERN’s particle accelerator, the famous LHC, was restarted on Tuesday July 4, parallel to the 10-year anniversary of the discovery of the Higgs boson. And on July 5, scientists announced that they had discovered three new “exotic” particles.
The idea of these experiments is to understand how matter is formed, at the most infinitesimal level, which can also help us understand how the universe was formed. The famous Higgs boson is also called the God particle, because at the beginning of the universe, particles had no mass. They have acquired one, thus allowing the formation of planets and stars, thanks to the Higgs field and therefore the boson associated with it. Its existence had been theorized in 1964 but only proven in 2012.
A zoo 2.0
The same goes for the new particles discovered at CERN. These exotic particles were predicted more than half a century ago but they have only been discovered for about twenty years thanks to the LHC. “The more analyzes we do, the more types of exotic hadrons we find,” explains in a press release Niels Tuning, physics coordinator for the LHCb experiment (LHC beauty). We are now living in an era of discovery similar to that which we experienced in the 1950s, when we began to discover a veritable “zoo of particles” – in this case hadrons. This is how the quark model for classical hadrons was developed in the 1960s. We are creating a “particle zoo 2.0”.
Hadrons are a large family of composite particles which themselves contain several sub-families, the best-known examples of which are nucleons, ie the protons and neutrons forming the nuclei of atoms. The H of LHC corresponds to them: Large Hadron Colliser, or large hadron collider. Neutrons and protons are themselves composed of smaller particles, quarks, they have three each.
But the exotic particles discovered have a different number of them. The three revealed this week are a new type of ‘pentaquark’ (with five quarks) and the first pair of ‘tetraquarks’ (four quarks) ever detected, featuring a new type of tetraquark. Quarks come in six “flavors”: up (u), down (d), charm (c), strange (s), top