CERN Milestone: First Heavy Ions In The LHC

CERN News: First heavy ions in the LHC

The LHC runs led ions for the first time, reaching unprecedented collision energy. Interviews with Jürgen Schukraft (ALICE spokesperson), Bolek Wyslouch (CMS run coordinator), Peter Steinberg (ATLAS Brookhaven National Laboratory), William Brooks (ATLAS Brookhaven National Laboratory).



The CMS experiment at CERN's Large Hadron Collider (LHC) has recorded its first Lead-Lead collisions at a centre-of-mass energy of 2.76 TeV per nucleon pair, marking the start of its heavy ion research programme. Physicists around the world expect a wealth of new results and phenomena from these collisions, which occur at energies 14 times higher than previously achieved by the Relativistic Heavy Ion Collider (RHIC, Brookhaven, USA).

At 11:20:56, on 8th November the LHC Control Centre declared stable colliding beams of heavy ions. CMS immediately detected the first collisions, each producing thousands of particles whose trajectories are reconstructed in the CMS silicon detectors and whose energies are measured in the calorimeters. Moments later, the data were analysed and the first images of these events were produced.