Thursday, December 22, 2011

CERN finds a new particle, but it's not Higgs

The group of scientists at CERN, Switzerland have just announced that their ATLAS detector has discovered a new particle. By smashing protons at insanely high speeds in the Large Hadron Collider, they found a particle that is described as Chi-b (3P). It tells us more about the fundamental forces of nature, but the Swiss organization is actually looking for the Higgs boson; the particle that is supposed to complete the Standard Model by explaining why particles possess mass.

A Chi-b (3P) particle consists of two elements, both being quarks. Quarks are the building blocks for protons and neutrons, which in turn make up an atom. The difference between the two quarks, which are called 'beauty', is that they are mirror images: one quark is formed of matter as we know it, while the other one is an anti-quark. While a particle paired with an anti-particle is not normally observed in nature, we are able to create them by smashing particles at high speeds in long tubes such as the Large Hadron Collider.

Antimatter is described as the mirror image of normal matter. It behaves in the exact opposite way as what we are used to. A particle combined with an anti-particle is not something we observe in every day situations: if matter meets antimatter, they annihilate each other and release massive amounts of energy, which is described by Einstein's famous E=MC2 equation. That is why these pairs, which are called mesons, do not live very long. It also highlights that you should not shake hands with your antimatter self, as you would be annihilating the both of you. It is hypothesized that the early universe consisted of equal amounts of matter and antimatter, but matter prevailed because of a certain asymmetry in the rate at which it decays. In the end, only matter survived.

The strong force
While Chi mesons were already discovered, the variant that CERN published is a bit different. From the way both 'beauty' quarks are connected with each other, scientists are able to learn more about the strong force, which is one of the four fundamental forces of nature. It explains how particles connect to each other, and, for example, can form an atom core. While it may not be as exciting as finding the Higgs boson that is supposed to complete the Standard Model of physics, it does give us more insight in how the world around us works.

Unifying theory
Their findings can help scientists make more accurate unifying theories, that combine the four fundamental forces. In addition to the strong nuclear force, there is the weak nuclear force, which is responsible for what we observe as nuclear radiation. The other two forces are electromagnetism and gravity, which are mostly known to the general public. Electricity and magnetism have been unified a long time ago, when scientists found that they have the same force-carrying particle: the photon, which is the particle of light. Electricity and magnetism are more or less different aspect of the same underlying force. The electromagnetic force can be explained by the exchange of photons.

Later, electromagnetism and the weak nuclear force were combined into the electroweak force. Combining that with the strong nuclear force proved to be harder, and gravity is as of yet nowhere to be found in these theories. Finding the Higgs boson could help us creating a complete and unified theory of all the forces into one formulation, but it may also give rise to new questions and make things even harder.

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