Higgs Particle Discovery: CERN LHC prepares for data pile-up

The world’s largest particle accelerator is roaring along at an unprecedented pace, delivering torrents of data to its physicist handlers. But the hundreds of millions of collisions happening inside the machine every second are now growing into a thick fog that, paradoxically, threatens to obscure a fabled quarry: the Higgs boson.

The problem is known as pile-up, and it promises to be one of the greatest challenges this year for scientists working on the Large Hadron Collider (LHC) at CERN, Europe’s main high-energy physics laboratory near Geneva, Switzerland.

Huge amounts of computing power, cunning software and technical tricks are helping scientists to stay ahead of the problem. But researchers may still need to scale back the collisions to find the long-sought Higgs, the manifestation of a field that is believed to confer mass on other particles.

If it exists, the Higgs will appear fleetingly inside the machine before decaying into lighter particles. Last year, the two biggest detectors at the LHC saw hints of a Higgs with a mass of about 125 gigaelectronvolts (energy and mass are interchangeable in particle physics). This year, researchers want to collect more data to see whether that signal grows into a certainty, or withers back to nothing.

Since it began its latest science run last month, the LHC has been squeezing trillions of protons into ever-smaller bunches, and smashing those bunches together tens of millions of times per second.

The resultant data are measured in inverse femtobarns (fb⁻¹), a unit roughly equivalent to 100 trillion collisions. In the past month alone, the LHC recorded 1 fb⁻¹ worth of collisions. By the end of the year it aims have captured at least 15 fb⁻¹ (see ‘Smashing!’).

Tevatron tightens up the race with LHC for the Higgs - New Scientist

(Image: Fermilab)

Tevatron near Chicago could be in the running to discover the Higgs boson

WITH the Large Hadron Collider (LHC) still in the repair shop, the race to find the Higgs boson has become a lot tighter, thanks to the older and less powerful but functioning, Tevatron collider near Chicago.

"The Tevatron definitely has a chance," says Greg Landsberg of Brown University in Providence, Rhode Island, who works on one of the LHC's detectors.

With the LHC due to restart only in November at CERN near Geneva, Switzerland, the Tevatron has been gaining ground in the search for the Higgs, the particle thought to give mass to other elementary particles. At last week's Lepton Photon conference in Hamburg, Germany, Tevatron physicists said that by early 2011 they will have recorded enough data to allow them to either find or rule out the Higgs as predicted by the standard model.

Tevatron physicists said that by early 2011 they will have the data to either find the Higgs or rule it out

The LHC will have to sprint to catch up, and it won't be easy. While the LHC's higher energies should produce more Higgs particles, it will also boost the production of other particles that can mimic a Higgs, says Gordon Kane of the University of Michigan in Ann Arbor. Telling between the two will require a precise understanding of how the LHC's detectors are working, which takes time to develop.

The LHC, however, could become the first to find particles of dark matter, a search for which the Tevatron is not well suited