Physicists at the European Laboratory for Particle Physics (CERN) in Geneva were locked in a dilemma earlier this week: whether to gamble SFr30 million (US$17 million) following up results that could represent the first viewing of CERN's current holy grail, the elusive particle known as Higgs boson.
The data come from four different experiments done over the past six months using CERN's Large Electron–Positron (LEP) collider. But the LEP is scheduled to be switched off at the end of this month to allow construction of the Large Hadron Collider (LHC).
Keeping the LEP online would delay the LHC, possibly until 2006. This could give US scientists at Fermilab's Tevatron proton–antiproton collider time to pip CERN physicists at the post — particularly if the preliminary results provide a strong clue about the energy range to concentrate on.
Due to come online in 2005, the LHC will operate at energy levels of up to 14×1012 electron volts— high enough to detect the Higgs boson with certainty, if it exists.
“A number of events have been observed in LEP experiments that are consistent with the production of the Higgs boson, in combination with the Z boson,” says Roger Cashmore, CERN's director of research. But he points out: “Background processes throw up similar events, so more data will be needed to decide whether they are real.”
The bulk of the data were collected at between 206×109 and 207×109 electron volts, the highest energy at which LEP operates stably. The results gathered so far must be compelling enough to persuade CERN's research board that two more months of experiments would “turn the indications into a recognizable real discovery that would be accepted by the scientific community”.
“We don't want to be the scientists who go down in history as having missed Higgs,” says Tiziano Camporesi, head of CERN's DELPHI experiment, who is convinced that there is a strong case for taking the gamble. A firm decision was due on Tuesday evening.
CERN physicists failed to reach a consensus on Tuesday night on whether to recommended that the Large Electron-Positron Collider (LEP) be kept in operation for a further two months to look for more evidence of the Higg boson. No decision is now expected on whether to follow this course of action until CERN's research board meets next week (14 September).