European collider gets short reprieve

Chris Tully: Final days will help someone to the prize

Scientists at Cern, Europe's top particle physics lab in Geneva, Switzerland, have decided not to close down their Large Electron-Positron (Lep) collider for another month.

It will allow them more time to follow-up recent experiments which suggested they may have seen "shadows" of the so-called Higgs boson.

The Higgs has become something of a Holy Grail for physicists. According to the Standard Model of particle physics, it is the Higgs that explains why some other particles have mass.

According to commentators, the team that finds the Higgs first is almost guaranteed a Nobel Prize.

"It would be one of the greatest landmark achievements of physics," said Chris Tully, a Princeton University professor who has been working on the search for the Higgs boson at Cern.

Further events

The Lep collider, which has a 27-km (17-mile) circumference, will now continue operating until 2 November when it must be decommissioned to make way for the new and more powerful Large Hadron Collider.

The underground accelerator has a circumference of 27 km (17 miles)

However, even this extension is unlikely to provide enough time for the Cern researchers to track down and confirm the existence of the Higgs.

Professor Tully conceded Cern was far from having enough data to be able to claim "discovery", even if collision events during the next few weeks threw up further interesting data to support already "strong" evidence.

But any results would help other scientists, most likely those at Fermilab near Chicago, US, to make the final breakthrough, he said.

Subatomic debris

The Higgs boson was named after the UK physicist Peter Higgs, who postulated its existence more than 30 years ago.

He suggested that the Higgs gives rise to a field through which all other subatomic particles, such as quarks, gluons, photons and electrons, must pass.

As they interact with the field, the particles experience a drag - the more drag, the greater the mass; the less drag, the lighter the particle.

Scientists cannot see the field but they could infer its existence if they can find the particle associated with it in the subatomic debris that is produced when matter is smashed together at high energies in an accelerator like the Lep.

Opened in August 1989, the Lep is the largest accelerator yet built.