By Pallab Ghosh Science Correspondent
Scientists have discovered new ways to pack quarks, the smallest particles known to man.
These new structures only exist for a hundred-thousandth of a trillionth of a trillionth of a second, but they could 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 made up 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 one is unique, but researchers are excited about 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 that 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 chemical elements on the periodic table.
This is an essential first step in creating a theory and set of rules to govern the exotic mace.
In light of these new findings, physicists are discussing the issue at a special seminar Tuesday at CERN, the European Organization for Nuclear Research, home of the Large Hadron Collider.
Studying the minute differences between the tiniest things we know can seem overwhelming, but the interaction of quarks creates what is known as the “strong force,” which holds the interiors of atoms and, by extension, the entire universe together.
“The strong force is extremely difficult to calculate, and we don’t have firm predictions of how exotic pentaquarks and tetraquarks are built,” says Professor Chris Parkes of the University of Manchester.
“But we hope that by discovering them, we can develop theories that 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.
In the late 19th and early 20th centuries, experimental results showed that atoms were made up of smaller particles: electrons, neutrons, and protons.
In the 1960s, it became clear that neutrons and protons were made of even smaller particles, called quarks, and that the interaction of quarks was related to one of the fundamental forces of nature, the strong force.
Not only does this force hold the interiors of atoms together, it plays an important role in the interactions of other subatomic particles that make the Universe work.
The Large Hadron Collider has undergone a major upgrade and the researchers involved believe they will discover many more 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 short by human standards, but since these particles travel at nearly the speed of light, they would leave trails a few millimeters long, which would be a valuable footprint for physical detectives to follow.