Scientists explain what form of matter they found at the Large Hadron Collider

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Physicists first encounter exotic, doubly charmed tetraquark

A discovery at the Large Hadron Collider. A group of scientists, which includes Novosibirsk physicists from the Institute of Nuclear Physics named after G.I. Budker RAS discovered a new particle of matter – an exotic tetraquark.

“The particle called Tcc + stands out strongly among its fellows and represents a new form of matter. This is the only doubly charmed tetraquark known to science, that is, it contains two charmed quarks at once, but does not have the expected charmed antiquarks, ”the scientists report.

In the name of the new tetraquark Tcc +, the letter “T” means that it is a tetraquark, “cc” – that it contains two charmed quarks (from “charm”), and the total positive charge indicates that the particle also includes anti-u -quark and anti-d-quark.

“The particle has unique properties and is actually a new form of matter,” explained Alexander Bondar, a member of the LHCb collaboration, head of the laboratory at the INP SB RAS, Academician of the Russian Academy of Sciences. – c-quarks included in the new tetraquark are relatively heavy: each has a mass of 1.5 times the mass of a proton. The particle has a positive charge (+1) and a mass of approximately 3.875 GeV. “

One of the possible internal structures of a new particle. Photo: cern.ch

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.

Kirill Ivanov, a high-energy physics researcher at the Moscow Institute of Physics and Technology, comments:

– A tetraquark is a particle that can form in a collider as a result of the collision of protons along with other particles. Despite the fact that about a dozen tetraquarks have already been found, this one is a more interesting variant, a new type, which have not yet been found.

When we discover these new particles and measure their properties, we begin to better understand exactly how strong interactions work. As a result, our measurements help theoretical physicists better understand how particles interact, how matter and our world as a whole are built from them.

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