Quarks are those tiny particles that make up every little thing that exists in the universal. And they still remain a deep mystery to physicists – even after 53 years when scientists first suspected that they exist. These little guys bounce around the edges of the accuracy levels of the scientific instruments that attempt to detect them. Researchers try to corral them away from the larger particles, and then decay them from their highest forms to their simplest form in about 50% of the time required for a light beam to move over a grain of salt. Amazing stuff!
This is why it has taken more than fifty years for scientists to validate the existence of a very exotic particle that they have searched since quark science began: the huge (in subatomic particle dimensions), elusive tetraquark.
Amazing Quark Discovery
Two physicists named and Jonathan Rosner of the University of Chicago and Marek Karliner of Tel Aviv University have recently confirmed that this massive, strange tetraquark can definitely exist in its truest form – which is four particles that interact with each other within one single, larger particle, and have no barriers to keep them apart. They have learned it is stable, and most likely can be generated at the Large Hadron Collider, which the a great particle smasher located at the CERN particle physics lab in Switzerland. They are set to post their report in a future issue of the Physical Review Letters.
What is a quark anyway?
If you have read even a little bit in the topic of particle physics, then you already know that all things with mass is comprised of atoms. When you dive just a little bit deep into particle physics, you would know that the atoms are made up of subatomic particles — the basic ones are neutrons, protons, and electrons. And then if you went even deeper, we would be talking about quarks.
Protons and neutrons are the more ordinary examples of a particle class called hadrons. If you were able to peek into hadrons, then you would see that it is comprised of even more tiny particles, and those are quarks.
While atoms take on different characteristics which depend on the proton and neutron combination that exist in their nuclei. Hadrons depend on the quark combinations that reside in their nuclei. You may be wondering about electrons. Electrons are not made up of quarks because they are not hadrons – they are leptons. Confused yet?
Believe it or not, quarks come in one of six different flavors. Their flavors are up, down, charm, top, strange, and bottom. Up and down quarks are by far the most common, the other four exist in very extreme circumstances – such as when the big bang occurred.
Playing with colors
“The suspicion had been for many years that [the tetraquark] is impossible,” Karliner said recently.
This is because the laws of physics indicated that four quarks could not ever bind together into a hadron that was stable. The reason is this. Where atoms are bound by the charges of the protons and electrons at its nucleus, hadrons are not quite the same because quarks have three different types of charges which are identified as colors – green, red, and blue.
Each quark is capable of have any colored charge. But when hadrons are formed, it must have a net charge of zero. So if it has a red quark, then there must also be blue or green quark too.
So, Karliner said, it is not that hard to envision a four-quark hadron. You just need to stick together two quarks of any kind to its two matching antiquarks. However, he warns that even if four quarks that match are stuck together, it doesn’t guarantee that they are still stable enough to form a hadron – they could still blow apart.
“Just because you move two men and two women into an apartment,” Karliner noted, “doesn’t mean they’ll settle down and form a nuclear family.”