Moscow. July 29. INTERFAX.RU – Collaboration of one of the experiments of the Large Hadron Collider, LHCb ( CERN, CERN, European Organization for Nuclear Research ), which includes physicists from Novosibirsk, announced the discovery of a new particle – an exotic tetraquark. The Institute of Nuclear Physics named after G.I. Budker (INP, Novosibirsk). The results are also published on the CERN website.
“The particle stands out strongly among its fellows and represents a new form of matter. It is the only doubly charmed tetraquark known to science, that is, containing two charmed quarks at once, but not having charmed antiquarks in its composition,” the message says.
The particle has a positive charge (+1) and a mass of approximately 3.875 GeV (one gigaelectronvolt is 1 billion electronvolts).
It is noted that the particle is a long-lived record holder – its lifetime is about 10-500 times longer than particles with a similar mass.
A tetraquark is an exotic elementary particle, a hadron, made up of two quarks and two antiquarks. Exotic tetraquarks are called because it was originally believed that hadrons can consist of either a quark-antiquark pair (such a hadron is called a meson), or of three quarks (in this case, a hadron is called a baryon; baryons are, for example, a proton or neutron).
“A lot of baryons and mesons are known, and they are well studied. However, more than 50 years ago it was assumed that there are hadrons consisting of four or even five quarks – tetraquarks and pentaquarks. At the moment, 4 pentaquarks and about 20 tetraquarks have already been experimentally discovered.” , – noted in the message.
LHCb ( Large Hadron Collider beauty experiment ) is one of the detectors of the Large Hadron Collider; in total, 62 new elementary particles have been discovered at the LHC since the start of the collider.
The LHCb experiment involves five people from INP and Novosibirsk State University.
A quark is a fundamental particle that is not observed in a free state, but is part of strongly interacting particles such as protons and neutrons. Quarks are structureless, pointlike particles. Enchanted are quarks with a positive charge equal to two-thirds of the elementary electric charge and a mass of 1.25 GeV, they occupy the third place in mass among quarks.