A few days ago, CERN announced that 4 new particles were discovered at the LHC (Large Hadron Collider), located in Geneva. This brings the tally of particles discovered by the LHC to 59.
The LHC is the world’s largest particle collider. It smashes particles together (mainly protons) to probe the quantum world and forward our understanding of the universe at the smallest of scales. It is putting our theoretical framework of particle physics to the test- the Standard Model of particle physics.
LHC’s last greatest discovery was the Nobel prize-winning Higgs Boson in 2012. The Higgs Boson was one of the last missing particles in the standard model but the theory is still far from complete- about 95% of the universe is made up of dark matter and dark energy and there are no corresponding particles for the “dark stuff” in the standard model.
The four new particles that were discovered recently are all tetraquarks with a charm quark pair and two other quarks. But wait a second, what are quarks?
All the stuff in the universe is made up of atoms. The atoms are made up of protons and neutrons and these are in turn made of quarks. Quarks are fundamental particles of nature, meaning they are indivisible. There are 6 types of quarks- up, down, top, bottom, strange, and charm. But, only 2 of them make up all matter in the universe- up and down. Each of them has a corresponding anti-particle as well- same mass, opposite charge.
The proton is made of 2 up quarks and 1 down whereas the neutron is made of 2 down quarks and 1 up. These quarks are held together by the strong nuclear force, the most powerful force in the universe. Gluons are the carrier/messenger particles of the strong force which are continuously exchanged among these quarks to produce the strong force.
These quarks can combine to make many different kinds of particles. For example, 3 quarks together make up “baryons”, a quark-antiquark pair make up masons, etc.
So the above few paragraphs gave the basic description of quarks and what holds these quarks together. But what did we learn or will learn through the discovery of these new quarks?
These new particles will expand our understanding of the universe and the standard model. The more particles we discover, the more we learn. These 4 new quarks may allow us to understand why every tetraquark has a charm-quark pair and more!