Large Hadron Collider hits the bottomium

Race to the bottomium: down the mind-blowing spiral of subatomic physics. Flickr/marc_buehler.

A heavy variant of a particle first observed 25 years ago has been found in the debris of close-to-the-speed-of-light proton collisions in the Large Hadron Collider at Geneva.

The particle Chi-b(3P) is an excitation (or energised state) of a particle that itself is difficult to create and detect – a particle formed by binding a ‘bottom’ quark (sometimes called the beauty quark) to its anti-quark counterpart. The bound particle is known as bottomium.

The discovery of Chi-b(3P) was made by the multinational ATLAS team, who uploaded their findings this week onto the open access repository, arXiv.org.

Bottomium is predicted by the Standard Model of particle physics but other models and techniques are required to calculate the particles’ properties, said Dr Jonathan Carroll, a Post Doctoral Research Associate at the University of Adelaide’s Centre for the Subatomic Structure of Matter.

“Quantum Chromodynamics (QCD), which describes the strong nuclear interaction between quarks, is a tremendously powerful model, but because of its behaviour, you can’t solve it exactly,” Dr Carroll said. Instead, physicists perform their calculations using “approximations to QCD:, Dr Carroll said, "including Non-Relativistic QCD and Lattice Gauge Theory.

"Lattice is breaking time and space up into little portions and doing calculations on them,” Dr Carroll said.

Hard yakka: a Lattice Gauge Theory lab. marc_buehler

The ATLAS experiments will continue into next year ahead of a shutdown of the Large Hadron Collider in 2013, when technicians will work on the collider’s power in order the energy at researchers’ disposal from 7 teraelectronvolts (7 TeV) per nucleon to towards 14 TeV.

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