ATLAS: Unlocking the Deep Mysteries of the Universe

These are exciting times for CERN (the European Organization for Nuclear Research). Since 1954 this little known research center, the largest of its kind, has been working to unlock some of the most elusive secrets of the universe. The particle physicists of CERN understand, as few others do, that the tiniest particles of matter are the key to understanding the infinitely large and expanding cosmos. With ATLAS, they have developed a technology and a device that allow them to test the theories of leading physicists the world over. 

ATLAS (A Toroidal LHC ApparatuS) is a multipurpose detector used to perform some of the most important experiments at the Large Hadron Collider (LHC) at CERN. It is used to evaluate the results of super collider experiments and to determine what happens to subatomic particles when they crash into one another at unimaginably high velocity. These experiments help us answer some of the fundamental questions in physics, such as: What are the fundamental forces of nature? What are the basic building blocks of matter? Could there be a greater underlying symmetry in our universe?
 

To better understand these questions, we have to analyse the behaviour of the collision of particles at incredibly high energies, creating similar conditions to those prevailing less than a picosecond after the “Big Bang”. The findings of ATLAS experiments can lead to discoveries that will unearth new theories that will enable us to better understand the Standard Model of quantum mechanics and thus the origins of the universe. An example of a recent finding, is the discovery of the Higgs Boson in 2012, which is very important because it helps us understand the mass of subatomic particles. When particles interact with the Higgs field, they gain mass. The stronger the interaction, the heavier the particle. Also, Higgs particles are very important because these were the particles that formed the universe in the first nanoseconds after the “Big Bang”. The discovery and investigation of Higgs Bosons is in effect the study of the origin of the physical universe. Let’s take a look at some of the things ATLAS experiments are hoping to uncover.
 
To understand the bigger picture we need to first understand the smaller one; and this is why physicists are studying the most fundamental building blocks of matter and searching for new ones that could be more fundamental. At the moment, the most fundamental particles that we have discovered are quarks and leptons; each of these has six types. Different combinations of quarks, make up more well-known matter such as protons and neutrons. Leptons do not undergo strong interactions and so exist in isolation. Electrons, muons and neutrinos are three of the leptons.
 
It is important to understand whether the building blocks of our universe are composed only of matter, or also of antimatter. Also, does dark matter actually exist? The former question is a little philosophical but the latter is very important to understanding the evolution of the universe. If we knew the mass of this dark matter and dark energy density we could predict whether the universe will undergo a “big crunch” or keep expanding forever. At CERN they are looking for particles that could make up this dark matter.