GENEVA — Scientists at the world's largest atom smasher said Monday they have succeeded in recreating conditions shortly after the big bang by switching the particles they use for collisions from protons to much heavier lead ions.
The Large Hadron Collider recorded its first lead ion collisions on Sunday and has since stabilized the twin beams sufficiently to start running physics experiments, said a spokeswoman for the European Organization for Nuclear Research, or CERN.
The collisions produce an effect that is as close as researchers have ever come to observing the state of matter moments after the formation of the universe, which is believed to have begun with a colossal explosion known as the big bang.
The event inside the collider "is a very, very, very small bang," CERN spokeswoman Barbara Warmbein told The Associated Press.
Still, researchers are hoping the collisions will be powerful enough to produce a thick soup of matter called "quark-gluon plasma" that will help them gain a deeper insight into how the universe began.
The $10-billion Large Hadron Collider was fired up in September 2008 and, despite some technical setbacks, has been hailed by scientists as a key tool for understanding or reshaping our knowledge about the universe.
Most of the time it will be used to smash together protons in the hope that one of the four giant detectors — situated around the collider's 17-mile (27-kilometer) tunnel under the Swiss-French border — will find evidence of dark matter, antimatter and maybe even hidden dimensions of space and time.
But for one month each year, before shutting down for winter maintenance in December, the Large Hadron Collider will smash together lead ions, said Warmbein.
Lead ions — which are lead atoms with the electrons removed — are much heavier than protons, meaning the energy used to circulate them is far higher.
"They are more likely to create the state of matter that ALICE is looking for," said Warmbein, referring to the detector that will be used to search for the plasma.
The resulting quark-gluon plasma, which is initially many times hotter than the sun, quickly cools, causing subatomic particles to stick together and form protons and neutrons. Scientists believe that by studying this process they will better understand how matter came into being.
Warmbein said that it will likely be months, if not years, before scientists make significant new discoveries.
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