Collisions between Lead Ions (IMAGE) University of Copenhagen - Niels Bohr Institute Caption One of the very first collisions recorded between two lead ions at the LHC's top energy. The energy in the center-of-mass system is approximately 1000 TeV. Todays events bring collisions physics into a new energy scale, that of PeV (Peta-electron-volts). The ALICE detector registered tens of thousands of particles. In this live display the tracks of the particles from the collision point and through the detector are shown in colors corresponding to their mass and type. Credit CERN Usage Restrictions CERN License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.