Scientists working with Hadron Collider (LHC) have discovered three subatomic particles never seen before as they work to unlock the building blocks of the universe, the European nuclear research center CERN said on Tuesday. The 27 kilometre- long (16.8 mile) LHC at CERN is the machine that found the Higgs boson particle, which along with its linked energy field is thought to be vital to the formation of the universe after the Big Bang 13.7 billion years ago. The new structures exist for just a hundred thousandth of a billionth of a billionth of a second, but may explain how our Universe is formed.
Atoms contain smaller particles called neutrons and protons, which are made up of three quarks each.
"Exotic" matter discovered in recent years is made up of four and five quarks - tetra quarks and pentaquarks. Now scientists at CERN say they have observed a new kind of "pentaquark" and the first-ever pair of "tetra quarks", adding three members to the list of new hadrons found at the LHC. Quarks are elementary particles that usually combine in groups of twos and threes to form hadrons, such as the protons and neutrons that make up atomic nuclei. More rarely, however, they can also combine into four-quark and five-quark particles, or tetra quarks and pentaquarks." The more analyses we perform, the more kinds of exotic hadrons we find," physicist Niels Tuning said in a statement.
"We're witnessing a period of discovery similar to the 1950s, when a 'particle zoo' of hadrons started being discovered and ultimately led to the quark model of conventional hadrons in the 1960s. We're creating 'particle zoo 2.0'.
"The strong force is extremely difficult to calculate, and we don't have firm predictions of how the exotic pentaquarks and tetra quarks are built," says Prof Chris Parkes of Manchester University. "But we hope that by finding out about them, we can develop theories that enable us to understand them better."
"What are quarks?
A Greek philosopher, Democritus, put forward the idea in the fifth century BC that the world was made up of indivisible particles, which he called atoms.
By the end of the 19th and early 20th century, experimental results showed that atoms were made up of smaller particles: electrons, neutrons and protons.
And in the 1960s, it became clear that neutrons and protons themselves were made from smaller particles still, called quarks; and that the interaction of quarks was tied to one of the fundamental forces of nature called the strong force.
The force not only holds the insides of atoms together, but is important in the interactions of other subatomic particles that make the Universe tick.
A pentaquark is a human-made subatomic particle, consisting of four quarks and one antiquark bound together; they are not known to occur naturally, or exist outside of experiments specifically carried out to create them.
The discovery of pentaquarks will allow physicists to study the strong force in greater detail and aid understanding of quantum chromodynamics.
A tetra quark, in particle physics, is an exotic meson composed of four valence quarks. A tetra quark state has long been suspected to be allowed by quantum chromodynamics,[1 hu] the modern theory of strong interactions. A tetra quark state is an example of an exotic hadron which lies outside the conventional quark model classification. A number of different types of tetra quark have been observed.
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