Production and study of antideuterium with the GBAR beamline

The potential of circulating antideuterons ( $$ ) in the AD/ELENA facility at CERN is under active investigation. Approximately 100 $$ per bunch could be delivered as a $$ beam based on measured cross-sections. These $$ could be further decelerated to $$ using the GBAR scheme, enabling the synthesis of antideuterium ( $$ ) via charge exchange with positronium, a technique successfully demonstrated with $$ antiprotons for antihydrogen production. The AD/ELENA facility is currently studying the possibility of increasing the $$ rate using an optimized new target geometry. Assuming this is feasible, we propose further enhancing the anti-atom production by using laser-excited positronium in the 2P state within a cavity, which is expected to increase the $$ production cross-section by almost an order of magnitude for $$ with $$ energy. We present the projected precision for measuring the antideuterium Lamb shift and extracting the antideuteron charge radius, as a function of the beam flux.

$$ production rate assuming 1e9 ortho- $$ from a flat target interact with $$ with $$ (blue) or inside a cavity (orange). Within the cavity, $$ can be excited to the 2P state, further increasing the charge exchange cross-section for $$ at $$ (green). Cross-sections are calculated using the Convergent Close Coupling (CCC, solid) method [36] and the Coulomb-Born approximation (CBA, dashed) [37].