August 18, 2015 – The Large Hadron Collider continues to give new views on the nature at the sub-nuclear scale. ALICE – A Large Ion Collider Experiment – is one of the four cameras as big as cathedrals, that at the CERN in Geneva look into the secrets of the very small. Here, a team of Italian physicists of the National Institute of Nuclear Physics proved the equality a fundamental property of nuclear matter and antimatter, the mass, to a level of precision never achieved before. The research was published on Nature Physics, the first for ALICE on this prestigious magazine. Thanks to the abundant production of light nuclei in the collisions between lead heavy nuclei, the Alice experiment is able to select a sample of one million nuclei of antideuterium and thousands of nuclei of the light antihelium isotope, and measure the difference in mass. This difference, within the experimental uncertainties, was equal to zero. The measurement confirms the validity of a fundamental symmetry of nature, the so-called CPT symmetry (Charge, Parity, Time), according to which if there is a core, then there is also an anti nucleus with the same mass but opposite charge.
