Washington, November 24 (ANI): The Large Hadron Collider (LHC) has circulated two beams 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.
With just one bunch of particles circulating in each direction, the beams can be made to cross in up to two places in the ring.
From early in the afternoon, the beams were made to cross at points 1 and 5, home to the ATLAS andCMS detectors, both of which were on the lookout for collisions.
Later, beams crossed at points 2 and 8, ALICE and LHCb.
"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," he added.
Beams were first tuned to produce collisions in the ATLAS detector, which recorded its first candidate for collisions at 14:22 this afternoon. Later, the beams were optimized for CMS.
In the evening, ALICE had the first optimization, followed by LHCb.
"This is great news, the start of a fantastic era of physics and hopefully discoveries after 20 years' work by the international community to build a machine and detectors of unprecedented complexity and performance," said ATLAS spokesperson Fabiola Gianotti.
"The events so far mark the start of the second half of this incredible voyage of discovery of the secrets of nature," said CMS spokesperson Tejinder Virdee from Imperial College London.
"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," he added.
These developments come just three days after the LHC restart, demonstrating the excellent performance of the beam control system.
Since the start-up, the operators have been circulating beams around the ring alternately in one direction and then the other at the injection energy of 450 GeV.
The beam lifetime has gradually been increased to 10 hours, and the beams have now been circulating simultaneously in both directions, still at the injection energy.
According to Professor Norman McCubbin, Head of Particle Physics at the Science and Technology Facilities Council's Rutherford Appleton Laboratory, "Achieving low-energy collisions in the LHC so quickly after the re-start is a huge boost for the worldwide particle physics community.
"We look forward eagerly to the next stages in commissioning the LHC and to embarking on our quest to unlock new secrets of the Universe as the machine becomes fully operational," he said. (ANI)