Large Hadron Collider: Big bang conditions

The Large Hadron Collider at CERN, a vast underground particle accelerator that costs 200,000 Swiss francs an hour to run, is designed to recreate the conditions of the Big Bang to allow particles such as the Higgs boson to be found and studied.

While the boson’s discovery would cement current knowledge about particles such as electrons and photons, proof that it does not exist would undermine the foundations of accepted theories of the make-up of the universe.

The particle is so short-lived that it can only be detected from the particles that it decays into. In the course of millions of collisions, the scientists are hunting for a significant excess of a particular combination of decay particles.

Although they are now converging on a particular profile for the Higgs, they will need another year’s worth of such collisions to rule out a statistical fluke.

“The window for the Higgs mass gets smaller and smaller,” said CERN Director General Rolf Heuer. “But please be prudent. Remember, we have not found it yet, nor have we excluded it yet. There is still Higgs hunting to be done.”

Oliver Buchmueller, senior physicist on the CMS experiment, said: “It can still happen that it is a fluctuation, but all we see from both experiments is compatible with what we would expect for a Higgs signal to build up...

“But we really need the data from next year to be sure of what we’re seeing.”

Claire Shepherd-Themistocleus, head of the CMS Group at the STFC Rutherford Appleton Laboratory, said: “We are homing in on the Higgs ...

“We have had hints today of what its mass might be and the excitement of scientists is palpable. Whether this is ultimately confirmed or we finally rule out a low-mass Higgs boson, we are on the verge of a major change in our understanding of the fundamental nature of matter.”