The largest, most complex scientific instrument in the world will begin its long-delayed hunt for new particles, forces and extra dimensions tomorrow (30MAR) at Cern, the European Nuclear Research Organisation, on the outskirts of Geneva.
Operators of the Large Hadron Collider (LHC) have set tomorrow morning as the moment the machine will attempt to steer speeding particles into head-on collisions, creating microscopic bursts of energy that mimic conditions that existed a fraction of a second after the Big Bang.
The start of high-energy operations at the collider marks the end of a frustrating 18-month delay for physicists who saw the machine shut down for essential repair work following an explosion at the laboratory in September 2008, just nine days after it was first switched on.
The GBP6bn collider, which occupies a 17-mile circular tunnel 100 metres beneath the French-Swiss border, accelerated two counter-rotating beams of protons to an unprecedented energy of 3.5tn electron volts (TeV) last week.
Tomorrow, the beams will be crossed for the first time in the highest-energy man-made collisions ever.
The machine was designed to collide two 7 TeV beams of protons, but laboratory managers decided in January to operate the machine at half power until the end of 2011. The machine will then close for a year of further engineering work to ensure it can run at full power in 2013 without breaking down again.
For scientists at Cern and elsewhere, the beginning of high-energy collisions tomorrow will end a long period of working without any real data. Until recently, physicists have had to make do with computer simulations of particle collisions. “There's a lot of anticipation here,” said David Wardrope, a British physicist at Cern. “So far, everything is looking good. We can do some real science now.”
The LHC broke the record for high-energy man-made collisions in November, when it smashed protons together at an energy of 2.36 TeV. The previous record holder, the US Tevatron collider near Chicago, operates at 1.96 TeV.
Tomorrow's collisions at Cern will be more than three times as energetic as those at the US laboratory. Much higher energy collisions take place constantly in nature, when particles in cosmic rays slam into clouds of interstellar gas, heavenly bodies and ions in the Earth's atmosphere. The Large Hadron Collider is expected to make new discoveries about the laws of physics at the highest energies and smallest scales ever probed.
Physicists hope these will help them decide which of their theories of nature are right and which should be junked.
Many physicists at Cern are almost certain they will find the Higgs boson, aka the “God particle”, which underpins a theory that explains where fundamental particles get their masses from. Finding the particle is a top priority for the US Tevatron collider, expected to shut down in 2011.
Cern researchers will sift through the subatomic debris of proton collisions for signs of extra dimensions and hitherto invisible particles that will bolster belief in “supersymmetry”, a theory that doubles the number of particle species in the universe. Other results may point to “hidden worlds” of particles and forces. — © Guardian News & Media 2010
