2 hours ago
By Pallab Ghosh Science Correspondent
Photo credit, CERN
“Exotic” states of matter exist for less than the blink of an eye.
Scientists have discovered new ways to group quarks, the smallest particles known to man.
These new structures only exist for a hundred thousandth of a billionth of a billionth of a second, but they might explain the formation of our Universe.
Atoms contain smaller particles, called neutrons and protons, which are made up of three quarks each.
The “exotic” matter discovered in recent years is composed of four and five quarks – tetraquarks and pentaquarks.
Scientists at the Large Hadron Collider in Switzerland have discovered a new pentaquark and two tetraquarks.
This brings the total number of discoveries to 21. Each is unique, but researchers are excited regarding the qualities of the three new discoveries.
The new pentaquark decays into particles that no other produces, while the two tetraquarks have the same mass, suggesting they may be the first known pair of exotic structures.
But perhaps even more importantly, the latest findings mean that there are now enough of these particles to start grouping them together, like the chemical elements on the periodic table.
This is an essential first step towards creating a theory and set of rules governing exotic mace.
In light of these new findings, physicists are discussing the issue at a special seminar on Tuesday at CERN, the European Organization for Nuclear Research, home to the Large Hadron Collider.
Studying the tiny differences between the tiniest things we know may seem daunting, but the interaction of quarks creates what is known as the “strong force”, which holds the insides of atoms together and, by extension , the whole universe.
“The strong force is extremely difficult to calculate, and we don’t have firm predictions of how exotic pentaquarks and tetraquarks are constructed,” says Professor Chris Parkes from the University of Manchester.
“But we hope that by discovering them, we can develop theories that will allow us to better understand them.”
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.
At the end of the 19th century and at the beginning of the 20th century, experimental results showed that atoms were made up of smaller particles: electrons, neutrons and protons.
In the 1960s, it became apparent that neutrons and protons were themselves made up of even smaller particles, called quarks, and that the interaction of quarks was related to one of the fundamental forces in nature, the force strong.
Not only does this force hold the interiors of atoms together, but it plays an important role in the interactions of other subatomic particles that make the Universe work.
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The Large Hadron Collider has undergone a major upgrade and the researchers involved believe they will discover many more such exotic particles, some of which may have six quarks bound together.
Some of them might have a less fleeting existence – perhaps a hundred billionths of a second.
That’s brief by human standards, but since these particles travel at near the speed of light, they would leave trails a few millimeters long, which would be a valuable footprint for physicist sleuths to follow.
