LHC completes proton run for 2015, preps for lead

The Large Hadron Collider (LHC) has successfully completed its planned proton run for 2015, delivering the equivalent of about 400 trillion (1012) proton-proton collisions – some 4 inverse femtobarns of data – to both the ATLAS and CMS experiments. LHCb and ALICE have also enjoyed successful data taking at lower collision rates. CERN engineers will now prepare the accelerator to collide lead ions, for a physics run due to start in late November. These heavy-ion collisions allow physi