Searching for elusive particles (Image: Fabrice Coffrini/epa/Corbis)

The Large Hadron Collider is flexing its muscles. A team at the collider in CERN, near Geneva, Switzerland, is set to publish the first result that surpasses the abilities of rival particle smashers.

The result concerns the search for an elusive “excited” quark. Quarks are not thought to be composed of anything smaller, but if one was found in an excited state, it would show this to be wrong. This is because an excited state only arises when there is a change in the way the smaller particles within are bound together.

Experiments at the Tevatron collider at Fermilab in Batavia, Illinois, have previously searched for excited quarks, and ruled out their existence at masses up to 870 gigaelectronvolts. Now the ATLAS detector at the LHC has extended this range by over 40 per cent, counting out excited quarks up to 1260 GeV.


Due to the LHC’s high energy, ATLAS achieved this with less than four months of data, compared with the four years needed for the Tevatron result. “Obviously we’re all very excited because we built this machine to get into a certain energy regime,” says Tom LeCompte of ATLAS.

“We’re already competitive with, if not better than, the Tevatron’s reach for a number of searches,” adds Albert De Roeck of the CMS experiment, another detector at the LHC.

Kurt Riesselmann, a spokesperson for Fermilab, says that despite this result, the Tevatron still leads the race to find other particles, such as the Higgs boson, because it has collected more data to sift through. “That’s where the Tevatron will hold the edge for a few more years,” he says.

Journal reference: Physical Review Letters, in press