Scientists at CERN have announced finding four new elementary particles at the Large Hadron Collider (LHC) in Geneva, Switzerland.
The four new particles bring the total of newly-discovered particles at the LHC up to 59 - including the popular Higgs boson particle - since it began conducting operational runs and "collided" protons together back in 2009.
LHC and Attempts to Finalize the Standard Model
Designed to explore the structure and interaction of matter at extremely short distances and high energy levels as a means of verifying the Standard Model of Particle Physics - which has been able to describe three of the four known fundamental forces (electromagnetic, weak, and strong interactions, leaving out gravitational force).
So far, it has advanced understanding of these fundamental forces through elementary particles. Among its most significant achievements is the discovery of the Higgs boson - first physically observed in July 2012 and subsequently confirmed by March 2013.
The discovery of this particle has led to the Nobel Prize for Physics being awarded to Peter Higgs and Francois Englert, two of the physicists who made theoretical predictions on the particle's behavior and characteristics since the 1960s.
As for the full explanation of the Standard Model, one of the challenging parts of the theory is the description of the strong force which is responsible for holding the nucleus of every atom together. Every nucleus contains protons and neutrons, each of which containing elementary particles called quarks.
Physicists suggest that if the strong force is deactivated for even a moment, all matter would immediately disintegrate into free quarks - itself a state believed to be existing at the very start of the Universe.
These quarks - which has never been observed alone - are known to interact through the strong force through the exchange of particles termed "gluons." It is generally explained as an analog to photons exchanged by charged particles through electromagnetic force. However, strong and electromagnetic forces behave very differently with respect to their particles, which keeps quarks in groups called hadrons.
Four New Particles in the Ongoing LHC Quest
The four new particles found in the LHC include tetraquarks - a meson of four valence quarks - as well as new mesons and baryons - containing heavy quarks such as the third massive of six quarks, the charm, and the bottom quark - known as a frequent decay product of the Higgs boson. The four new tetraquarks are reported in an article titled "Observation of new resonances decaying to J/ψK+ and J/ψϕ" now available on the online repository arXiv.
These particles are of interest to the scientific community since they demonstrate the additional potential combination of these quarks, however brief. Also, it is curious as to how the strong force connects these elementary particles together. One theory suggests that these new particles are compact materials, much like protons or neutrons. Another likens them to molecules, which are composed of hadrons loosely bound together.
Observing these new particles, and future potential discoveries, could further help address discrepancies between experimental and theoretical models. Additionally, the newly-discovered particles advance the LHC mission of understanding physics beyond the Standard Model. While widely accepted, the Standard Model of Particle Physics remain incapable of explaining other phenomena - such as the baryon asymmetry problem (the inequality between matter and antimatter in the Universe), or include the theory of gravitation as explained by the general theory of relativity.
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