Quark is an elementary particle, which combines to form the constituents of the nucleus, which are, protons and neutrons, or in other words “hadrons”. It has properties like an electric charge, mass, color charge, and spin. There are six types of Quark: Up, Down, Strange, Charm, Top and Bottom.
To study quarks, we need to look deeper into the nucleus which is made of protons and neutrons. RHIC is one type of experiment which is focused to study and explore Nature’s secret by going deep into atoms.
How They Do it?
RHIC (Relativistic Heavy Ion Collider) is the first machine in the world which can collide heavy ions. Ions meaning, atoms which do not have outer shell electrons. This machine, named RHIC uses Gold ions primarily because this is a very heavy element, and by colliding it can produce many particles.
What they do with these gold ions?
They first make the beam of Gold ions to travel at nearly the speed of light and then collide two beams head-on, which were traveling in opposite directions.
What will happen when these two high speed beams collide?
When they collide at such a high speed, this collision forces the nucleons (protons and neutrons) to melt for a small amount of time because of very high temperature, which in turn make gluons and quarks free. Gluons and Quarks are the constituents of protons and neutrons. Protons and neutrons are believed to be made of three quarks together with gluonic interactions.
Then after the collision, more and more particles form as the temperature goes down. All these particles give us some information or rather we can say “clues” of what happened during the collision.
Why should we study all this?
Everyone must have some questions in mind when we grow, Why the universe is the way it is, and What happened during the first moment of this universe?
Scientists believe that at the beginning of the universe, protons and neutrons were not there, only their constituents. As time passes and the temperature cools down, protons and neutrons start to form by combining quarks and gluons.
So, RHIC experiment is helping us to know what really happened at the first moments of the universe, in short, they are taking us back in time, to know how they really behaved at the beginning of the universe. These experiments are interdisciplinary, they are applied in various physics disciplines like nuclear physics and condensed matter physics.
Another thing which we know about proton is they have spin 1/2, but how they do have this number, because as the theory says if we combine all the spins of its constituents, it gives less than 1/2, so from where the proton is getting extra spin value. To find a solution to this interesting problem, RHIC experiments are very important. Proton spin can be very helpful to know more about the universe by studying some properties.
Why studying about Quark Matter is important?
The history of modern technology and engineering developments can be seen as a series of explorations with increasing technology to look deeper into the microscopic structure of matter. Since the beginning of humankind, science has always been a subject for questioning what we are made of, why we are here, what is going to be the future, and what is the smallest unit of matter which forms the universe.
To satisfy human curiosity, many discoveries happened during last centuries:
> Atoms are divisible
> Nucleus also have constituents
> Particles also have wave like properties
> Particles have various properties like spin and magnetic moment
> Discovery of Quarks and Gluons
During the journey of such profound discoveries in science and technology, humans have gathered knowledge to find ways to study matter at the smallest scales by building experiments using technological knowledge. Nowadays, the technology relies on a basic understanding of the structure and properties of matter.
Technology is so advanced, almost everything can be done on a simple mobile phone which is just as big as the palm of the hand. By doing RHIC experiments, scientists are able to study and discover more about the fundamental properties of matter and know how they behaved at the beginning of our universe.
From history, we can learn two things that:
> By going deeper and deeper into the structure of matter and studying about it, we can have the understanding of the matter which make this universe.
> And to go deeper we need technological revolutions which in turn benefit the human race.
For Further Reading:
• RHIC, BNL (https://www.bnl.gov/rhic/)
• ALICE Experiment, CERN (https://home.cern/science/experiments/alice).
• Free the Quarks (http://www.slac.stanford.edu/pubs/beamline/31/2/31-2-rajagopal.pdf).
• QCD Matter (https://en.wikipedia.org/wiki/QCD_matter).
Rajeev Singh, 1st-year Ph.D. Research Fellow at Institute of Nuclear Physics Polish Academy of Sciences, Krakow Poland.