First collisions occur in the LHC

NOV 23, 2009

Physics Today

Physics Today : The Large Hadron Collider (LHC) has circulated two beams (at 450 GeV) simultaneously for the first time, allowing the operators to test the synchronization of the beams and giving the experiments their first chance to look for proton–proton collisions.Early in the afternoon, the beams were made to cross at points 1 and 5, home to the ATLAS and CMS detectors; later, beams crossed at points 2 and 8, home to the ALICE and LHCb experiments.

The ATLAS detector recorded its first candidate for collisions at 14:22 Central European Time.

“It was standing room only in the ALICE control room and cheers erupted with the first collisions,” said ALICE spokesperson Jurgen Schukraft. “This is simply tremendous.”

“The tracks we’re seeing are beautiful,” said LHCb spokesperson Andrei Golutvin, “we’re all ready for serious data taking in a few days time.”

Collisions at CMS

“It’s a great achievement to have come this far in so short a time,” said CERN Director General Rolf Heuer. “But we need to keep a sense of perspective—there’s still much to do before we can start the LHC physics program."Next on the schedule is an intense commissioning phase aimed at increasing the beam intensity and accelerating the beams. All being well, by Christmas, the LHC should reach 1.2 TeV per beam, and have provided good quantities of collision data for the experiments’ calibrations.