After a few anxious hours of delay following some electrical glitches, the Large Hadron Collider (LHC) got off to a glorious start on its research programme at an unprecedented realm of energy towards our understanding of the universe. Around 4.30 pm IST on March 30, the two counter-rotating beams of protons in the 27-km-long underground ringed particle accelerator at the European Organisation for Nuclear Research (CERN) in Geneva attained the intended peak energy of 3.5 trillion (tera) electron-Volt (TeV) each and were successfully brought to collide against each other. The LHC suffered a mishap soon after its commissioning in September 2008, so the success must taste the sweeter for the accelerator physicists and engineers who have toiled to get it up and running. It was a great day for particle physicists round the world. This breakthrough has set the stage for a potentially rich harvest of new physics during the LHC's scheduled continuous run for 18-24 months at a record-shattering total available collision energy of 7 TeV, which is 3.5 times the energy reached so far at the Tevatron accelerator at Fermilab, USA. This will do no less than recreate the conditions of the early universe. Although the intensity of the beams during the first collisions was kept at orders of magnitude below the designed value, at its peak value the collision rate will be hundreds of millions of events per second as against 50-100 per second seen in the first run that lasted about three-and-a-half hours. But these hundreds of thousands of collisions recorded on Day One by the six experiments located around the accelerator circumference will keep the scientists busy. They may already harbour new physics to answer some of the questions that physicists are asking.
Is the hypothetical Higgs Boson for real? The Standard Model, an otherwise highly successful theory of matter and forces at lower energies, requires this elusive particle to explain the origin of mass to all matter. Is physics at terascale energies governed by supersymmetry? Are quarks and leptons the fundamental constituents of matter, as it seems at lower energies? Does the universe have curled up higher dimensions beyond the four that we see? Visible matter — the stars and the galaxies — is believed to make up only five per cent of the universe. What constitutes dark matter and dark energy, which account for the rest? The LHC has thus embarked on a new journey of discovery. In realising this, the 50 Indian physicists participating in the experiments have played a significant role. In the months to come, thousands of scientists around the world will be poring over petabytes of data that could reveal completely unexpected physics — beyond the known and the expected.
(This article has been corrected. The expansion of CERN, as pointed out by one of our online readers, was incorrectly published initially.)
