Cloud of Positronium, an Exotic Matter-Antimatter System, Laser-Cooled for the First Time

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Feb 23, 2024/ Off Comments / in Announcement / by

Positronium (Ps), an exotic atom consisting only of an electron and its antimatter particle, the positron, is the lightest known atomic system. The AEgIS collaboration at CERN experimentally demonstrated, for the first time, Ps laser cooling using a particular laser system (alexandrite-based), specifically developed to meet the requirements of cooling: high intensity, large bandwidth and long duration of the pulse. The equivalent temperature of the Ps atoms exiting from a porous target (at room temperature) hit by a positron beam decreased from 380 K to 170 K, corresponding to a decrease of the transversal component of Ps rms velocity from 54 km/s to 37 km/s.