The Large Hadron Collider is known to be an incredibly complex machine. Among the main tasks of a charged particle accelerator is the acceleration of protons and heavy ions and the study of the products of their collisions. So when they say “these sorcerers-scientists break matter into atoms”, everything is true, except, of course, that scientists are not sorcerers. New study, the results of which have been presented during an international scientific conference on physics, confirmed the existence of a previously unknown particle, which is a tetraquark – an exotic hadron containing two quarks and two antiquarks. It is the longest-lived particle of exotic matter that researchers have ever discovered, and the first to contain two heavy quarks and two light antiquarks. And before you get completely confused, recall that quarks are the fundamental building blocks from which matter is built. These subatomic particles combine to form hadrons – a group of familiar protons and neutrons (in other words, quarks are smaller than just small.) Protons and neutrons are made up of three quarks, but the newly discovered hadron particle is made up of four, making it a kind of tetraquark – a completely new particle.

The world of elementary particles

Elementary particles, although invisible to the human eye, constitute both ourselves and everything that surrounds us. When talking about quarks, it is important to understand that they differ from each other in mass and charge . The new tetraquark is the first exotic hadron that scientists call fascinating. The reason is that two of its quarks are present next to antiquarks, but they are not charming at all.

Quarks can be thought of as Lego bricks, so simply discovering a new combination of four quarks that haven’t been seen before is not as exciting as it sounds. What’s interesting to study is HOW these particles come together – by understanding these processes we can finally learn how quarks stick together, ” said Freya Blackman, a physicist at Vrieux University in Brussels who was not involved in the study. I think this is a very exciting result.

So, the new particle contains two quarks and two antiquarks – the evil twins of a quark, if you can call them that. In recent years, several tetraquarks have been discovered (including one with two quarks and two antiquarks). The new discovery of physics is especially highlighted, since particles containing a quark and an antiquark have, in their words, a “hidden charm.”

Why is a tetraquark a special particle?

Exotic particles like the new tetraquark can be created in accelerators like the Large Hadron Collider, but they come and go extremely quickly. It is believed that the new tetraquark exists for quite a long time before decaying. But “long” in this case is an incredibly short period of time during which this particle can hardly be measured in our, excuse me, human terms.

The life span of the new tetraquark is probably slightly more than one quintillion second, ”said Patrick Coppenburg, a physicist at the Dutch National Institute for Subatomic Physics and a member of the LHCb team at CERN.

Like many other quark states, the new particle was discovered by physicists using a method called hit hunting. Basically, the researchers fire up a particle accelerator and allow the particles to collide, tracking an unexpected amount of energy or mass in the system. When they get results that are out of sync with the main noise of the system and have filtered out all irrelevant signals, physicists have a clue that they have stumbled upon something new.

Note also that the results obtained with the LHC help physicists understand how fundamental particles interact . As for the new tetraquark (scientifically written as Tcc +), it decays slowly, as it is only slightly heavier than the particles into which it decays. Previous LHCb results allowed theoretical physicists to predict in 2017 that a similar tetraquark, called Tbb, could be completely stable, which means it won’t decay at all due to the strong interaction.

It will be a breakthrough in particle physics if the discovery of a new type of tetraquark with two heavy quarks and two light antiquarks is proven, ”said Rui-Lin Zhu, a theoretical physicist at Nanjing Normal University in China. The new discovery is an absolute triumph of theoretical predictions.

In general, the new experiment confirms the conclusions previously obtained by the researchers: “now we know that it is the particles that rule the hadronic universe,” physicists note . Moreover, the discovery opens the way for the search for heavier particles of the same type, with one or two quarks. Well, the new particle is a very tempting target for further study.

The fact is that the particles into which a tetraquark decays are relatively easy to detect, and combined with the small amount of available decay energy, this leads to excellent accuracy in determining the tetraquark mass and allows you to study the quantum numbers of this fascinating particle. This, in turn, can provide a rigorous test of existing theoretical models and could even potentially allow exploration of previously unattainable effects. Science, go ahead!