CERN first discovered an exotic particle consisting of four charmed quarks. About the discovery reported in the article published in the repository of preprints arXiv.org.
A team of scientists used the new method to find anomalies in particle physics called “benami” (eng. bump), compared to other products recorded collisions (events) beams of protons accelerated in the Large hadron Collider with energy up to 13 teraelectronvolt. The researchers reviewed data collected in the period 2009-2013 and 2015-2018 detector of LHCb, and found a “bump” in the distribution of masses of particles (J/ψ-mesons), consisting of a charmed quark and a charmed antiquark. The observation was made with a confidence level of more than five Sigma (five standard deviations) that allows scientists to talk about the existence of new, previously unknown particles.
“Bump” corresponds to the resonance (short-lived particle) with a mass range of 6.2 and 7.4 GeV/C
(GeV on the speed of light squared), which is projected corresponds to a particle consisting of two charmed quarks and charmed the two recorded the creation, that is, it refers to tetraquarks. It is not yet clear whether the new particle a real tetraquark, that is, a system closely related to each other particles, or “hadron molecule” — two closely interacting mesons, i.e. particles consisting of a pair quark-antiquark.
LHCb is one of four main detectors installed at the Large hadron Collider and is designed to search for anomalies in interactions composed of quarks of particles. The main goal of the experiment is the discovery of New physics beyond the Standard model, which describes interactions of all known elementary particles.