November 8, 2010
LHC Successfully Smashes Lead Ions Together
The Large Hadron Collider (LHC) has taken new steps by smashing together lead ions instead of protons to create a "mini-Big Bang."
Scientists working at the particle smasher achieved the feat on November 7.
The LHC lies under the French-Swiss border near Geneva in a 16-mile long circular tunnel.
The world's highest-energy particle accelerator has been colliding protons in search for the Higgs boson particle. This elusive particle could help shed light on the new physical laws.
However, scientists at the LHC will concentrate on analyzing the data obtained from the lead ion collisions.
It only took four days for the LHC operations team at the European Organization for Nuclear Research (CERN) to complete the transition from protons to lead ions.
"The speed of the transition to lead ions is a sign of the maturity of the LHC," CERN Director General Rolf Heuer said in a press release. "The machine is running like clockwork after just a few months of routine operation."
They hope to learn more about the plasma the Universe was made of a millionth of a second after the Big Bang, 13.7 billion years ago.
ALICE, one of the LHC's experiments, was specifically designed to smash together lead ions. However, the ATLAS and Compact Muon Solenoid (CMS) experiments have also switched to the new mode.
"It's been very impressive to see how well the LHC has adapted to lead ions," said Jurgen Schukraft, spokesperson of the ALICE experiment. "The ALICE detector has been optimized to record the large number of tracks that emerge from ion collisions and has handled the first collisions very well, so we are all set to explore this new opportunity at LHC."
David Evans from the University of Birmingham is one of the researchers working at ALICE.
He said the collisions obtained were able to generate the highest temperatures and densities ever produced.
"We are thrilled with the achievement," Evans told BBC.
"This process took place in a safe, controlled environment, generating incredibly hot and dense sub-atomic fireballs with temperatures of over ten trillion degrees, a million times hotter than the centre of the Sun."
"At these temperatures even protons and neutrons, which make up the nuclei of atoms, melt resulting in a hot dense soup of quarks and gluons known as a quark-gluon plasma."
Quarks and gluons are sub-atomic particles, which are the building blocks of matter. During the quark-gluon plasma state, they are freed of their attraction from one another, which is what is theorized to have taken place just after the big bang.
Evans said that by studying the plasma, physicists hoped to learn more about the strong force that binds the nuclei of atoms together.
After the LHC finishes colliding lead ions together, it will go back to smashing protons again.
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