Mini "Big Bang" recreated

Researchers working on the Large Hadron Collidecr (LHC) have managed to create a “mini Big Bang”.

LHC scientists at CERN, the European Organization for Nuclear Research, produced the effect by colliding lead ions together at speeds close to the speed of light, thereby generating the conditions of the beginning of the universe.

Since 30 March 2010, experimenters have been colliding protons onto protons, but they recently switched to lead ions.

Stripped of their electrons, these positively charged lead ions carry 82 protons rather than just one. The result of the collision was an enormous rise in temperature to about 10 trillion degrees, a temperature 1 million times hotter than the centre of the sun.

At such a high temperature, the lead ions break into their smaller parts, quarks and gluons, which travel freely and rapidly in a closely packed state of matter known as a quark-gluon plasma.

Researchers believe that this state of matter is a fundamental component of understanding the “Strong Force” which binds atoms together and is responsible for over 98 per cent of the universe’s mass. In the quark-gluon plasma state, the Strong Force does not exist and the atoms break apart.

Professor Franz Muheim, Head of the Institute for Particle and Nuclear Physics at the University of Edinburgh, explained: “The concept of nuclei, like protons and neutrons, doesn’t exist at this energy density.

"This is our way of looking backwards in time. We’ve just traveled so far back that we’ve come to a time when nucleons as we know now didn’t exist yet.”

Researchers are now in the process of analyzing the results and tracking the trajectories of the particles. The results come from the ALICE (“A Large Ion Collider Experiment”), one of the four main particle detector experiments occurring at the LHC.

The other three main experiments using the LHC are known as ATLAS (“A Toroidal LHC Apparatus”), CMS (“Compact Muon Spectrometer”), and LHCb (Large Hadron Collidor beauty experiment).

Given the exciting results of the ALICE experiment, The Journal spoke with Professor Muheim about the University of Edinburgh’s involvements in the LHC experiments. Approximately 25 physicists from the University, including academics, fellows, research associates and PhD students, are involved in LHC experiments.

“At Edinburgh,” Professor Muheim explained, “we are part of the LHCb, where we try to understand the matter/antimatter asymmetry”.

The University of Edinburgh has been involved with LHCb since 1999 and is currently the Principle Investigator of the 10 UK groups within the LHCb experiment. 

In addition, the University of Edinburgh is part of the ATLAS experiment, which looks at the Higgs boson, a hypothetical elementary particle that is seen as the “missing link” in particle physics.

Professor Muheim stressed the importance of understanding the latest LHC results: “We have to be a bit careful here. It sometimes scares people when you tell them you recreate the Big Bang. You recreate the condition of the Big Bang, but it’s a 'mini Big Bang'. The total energy amount is still miniscule, but the density at the collision is the same as it was 0.000001 seconds after the birth of the universe.”