LHC heads into new year with first particle discovery
The first new particle was seen at the Large Hadron Collider at CERN in Switzerland shortly before Christmas.
The ATLAS collaboration announced the discovery of the particle Chi-b (3P), which consists of a bottom quark and antiquark particle bound together by the strong force. This force holds all atomic nuclei together so understanding Chi-b (3P) could help physicists understand better how the tiniest components of matter hold together to form the basis of everything you see: planets, people, plants.
Theorists have long proposed the existence of the Chi-b (3P), but until now it was not observed at any experiments. The particle is slightly heavier than predicted, meaning the quark anti-quark pair are a little more loosely bound than expected.
"Normally, a new particle is discovered in one or at most two channels, and the first discovery is at the very edge of statistical significance. This time things are different: it’s seen in three different channels and the peak is unmistakable," according to an email by Tom LeCompte, the physics coordinator for the ATLAS collaborator and a physicist at Argonne National Laboratory outside Chicago. "The outstanding LHC performance is responsible for this by delivering so many collisions in such a short time."
The ATLAS collaboration consists of 3,000 physicists from 38 countries.
Chi-b (3P) particle belongs to the boson family of particles just as the sought-after Higgs boson does. While the Higgs boson is suspected of giving all particles mass, Chi-b (3P) could explain how the mass of various elementary particles join together to make more massive, complex structures.
The bound quark states that make up Chi-b (3P) are collectively called quarkonium, and are analogues of the hydrogen atom, with each new particle corresponding to a different energy level. As with the hydrogen atom, physicists can observe transitions between these states through emission of a photon, according to the ATLAS collaboration.
A publication has been submitted to Physical Review Letters.
Read the ATLAS white paper: "Observation of a new chi_b state in radiative transitions to Upsilon(1S) and Upsilon(2S) at ATLAS"
Popsci.com: LHC has discovered its first new particle
Science Daily: New Particle at LHC Discovered by ATLAS Experiment