Exotic subatomic particles that are like ‘normal’ particles apart from one, opposite, property—such as the positron, which is like an electron but positively rather than negatively charged—are collectively known as antimatter. Direct studies of collisions between particles of matter and those of antimatter using giant facilities such as those at CERN can advance our understanding of the nature of matter. A new study by Tasko Grozdanov from the University of Belgrade in Serbia and Evgeni Solov’ev from the Institute of Nuclear Research near Moscow in Russia has mapped the energy levels of an exotic form of helium produced in this way. This work, which is published in EPJ D, has been described by one commentator as ‘… a new jewel in the treasure of scientific achievements in atomic physics theory”.
Source:
https://phys.org/news/2020-03-frozen-planet-states-exotic-helium-atoms.html