LHC revs up

Atom smasher achieves most energetic collisions yet

By all accounts, the Large Hadron Collider’s first day of bashing protons was a smashing success. The powerful machine at CERN, Europe’s high-energy physics laboratory near Geneva, Switzerland, got off to a rocky start on March 30. But by early afternoon (Geneva time), two 3.5 trillion electron volt beams were colliding head-on.

The collisions in the 27-kilometer-long accelerator set a new record for the highest energy crash of subatomic particles.

“Today, we opened the door and put our nose through it,” says physicist Jurgen Schukraft, spokesperson for CERN’s ALICE experiment, which is tasked with exploring new types of matter produced in the high-energy collisions. 

Researchers have routinely circulated beams at 3.5 TeV since March 19, but had not yet collided them. Around 1 pm local time, CERN tweeted “Experiments have seen collisions!!!!!!!!!!!” followed quickly by “First time in the history!!!!!!!!!!!! World record!!!!!!!!”

In the first hour of collisions, scientists had already collected more data than they did in weeks before that. Experiments recorded data for more than three hours before ramping down for the day.

“Already it looks like we are entering new territory,” Schukraft says. But it will take “years, not days or weeks,” he adds, to answer physicists’ questions about theoretical predictions like the elusive Higgs particle, dark matter and supersymmetry.

A morning collision attempt was aborted when a piece of overly sensitive equipment detected errant electromagnetic radiation. Scientists resolved the issue, and by the early afternoon, “it was all ok,” Schukraft says. “It works perfectly.”

CERN plans to run the accelerator at 3.5 TeV per beam for the next 18 months to two years, with a brief maintenance break at the end of 2010. After experiments at this energy level are complete, the LHC will be shut down and prepared to run at its maximum energy of 7 TeV per beam. If all goes according to plan, the collider will begin operating at full power in 2013.

Schukraft dismisses fears that these kinds of high-energy collisions could produce a voracious black hole and swallow the world by pointing out that he is “standing rather close to the experiment” and still able to carry on a conversation.

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