Tetraquarks and pentaquarks: An "unnatural" exotic form of matter has been discovered
Scientists working at the CERN laboratory recently announced the discovery of exotic matter not seen in nature: two distinct “tetraquarks” and “pentaquarks,” all of which were created in the collision between pairs of protons colliding with each other at very close velocities. lamp speed. The energy from this collision is literally transmuted into these exotic particles, a process governed by Einstein’s famous equation E = mc2. They will provide a new method for studying the forces that bind atomic centers together.
What are quarks?
Quarks were proposed in 1964 by American physicist Murray Gell-Mann as a solution to a major problem at the time. From the late 1940s to the early 1960s, physicists discovered hundreds of particles with a dizzying array of masses, electric charges, lifetimes, and ways in which the particles interacted. So many different particles had been discovered with such diverse properties that researchers at the time referred to the zoo as a “particle zoo”. At the time of their discovery, these particles were the smallest known objects.
Gell-Mann solved the confusion when he realized that zoo particles are not the smallest objects in nature. In contrast, the inhabitants of subatomic zoos are made of even smaller particles: quarks. Gell-Mann’s original idea was that there are three types of quarks, which he called up quarks, down quarks, and odd quarks.
The heaviest particles known at the time were a combination of three quarks. For example, the familiar proton consists of two up and one down quark, while the neutron consists of one up and two down. The name for this heavy particle is “baryon”, from the Greek word new (“heavy”).
Particles of medium mass are called mesons, from meso (“middle”). Mesons consist of quarks and antimatter quarks. The most common meson is called the pi meson (“pawn”), and one particular pawn consists of an up quark and a down quark of antimatter. The lightest particles, called “leptons,” are taken from the Greek leptospirosis (“light”) is a completely different class of particles and does not contain quarks. The most famous are electrons.
While the quark theory explains much of the known particle zoo, it also predicts the existence of particles that had not been observed when the theory was proposed, for example, the “omega baryon”, consisting of three strange quarks. (However, the theory was validated months later, when baryon omegas were discovered.) Quarks are part of the Standard Model of particle physics, which is universally accepted in the scientific community.
While Gell-Mann originally proposed that there were only three quarks, scientists have now discovered a total of six. Their names are up, down, charm, weird, up, and down. In the last half century, researchers have discovered most of the possible ways they can combine all three at once, or as a pair of quarks and quark antimatter.
Not just a trio, but a quartet and a quintet
However, in Gell-mann’s original paper, he did not limit the possible configurations of quarks to three-quark baryons and quark-antiquark pair mesons. He also postulated a four-component “tetraquark” (made of two quarks and two antiquarks) and a five-component “pentaquark” (made of four quarks and one antiquark). Searches for these particles have been unsuccessful for many years, but in more recent times, candidate particles have occasionally been detected.
In recent years, an experiment at the CERN laboratory, called LHCb, has been trying to find a previously unknown particle. His recently announced discovery is not an entirely new class of matter — after all, a handful of tetraquarks and pentaquarks are known to exist — but rather a new variant.
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Two of these particles are tetraquarks. One of them consists of charm quarks, up quarks, down antiquarks, and strange antiquarks; the others consist of charm quarks, down quarks, rising antiquarks, and strange antiquarks. (Note: Antiquarks are denoted by a line above the letter.)
Another new particle is the pentaquark, consisting of charm quarks and their antiquarks in combination with ascending, descending, and odd quarks. This is the first pentaquark found to contain a strange quark.
The importance of exotic material
So, what is the importance of finding new examples of very exotic forms of matter? This allows us to better understand the nature of the strong nuclear force under extreme conditions. (The strong nuclear force is responsible for, among other things, holding atomic nuclei together.)
It also has implications for our understanding of the very early evolution of the Universe. Shortly after the Big Bang, the Universe was so hot that quarks were free to roam around and not be trapped inside larger particles. About a millionth of a second after the Big Bang, the Universe cooled enough that the strong nuclear force began to collect quarks in the protons and neutrons that make up the cosmos, but during the transition, it must have assembled tetraquarks and pentaquarks as well. While these primordial particles have long since decayed, a complete calculation of the origin of the Universe will require an understanding of tetraquarks and pentaquarks.
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