Antideuteron production from beauty-hadron decays: a first phenomenological study

Light antinuclei, such as antideuteron ($\bar{\mathrm{d}}$) and antihelium (${}^{3}\overline{\mathrm{He}}$,${}^{4}\overline{\mathrm{He}}$), provide a link between collider physics and indirect Dark Matter searches. Despite extensive studies of antinucleus production in high-energy collisions, $\overline{\mathrm{d}}$ production from beauty-hadron decays remains experimentally unconstrained and has not yet been quantitatively predicted. In this work, we present the first phenomenological study of $\overline{\mathrm{d}}$ production from $\overline{\Lambda}_{b}$ baryon and B$^{-}$ meson decays, providing the first estimates of the corresponding branching ratios. Beauty-hadron decays are simulated with PYTHIA using realistic input kinematics and three hadronization scenarios. Antideuteron formation is modelled through a quantum-mechanical coalescence approach based on an $\bar{\mathrm{d}}$ wave function derived from the Argonne $v_{18}$ nucleon-nucleon potential. Depending on the adopted hadronization model, we estimate inclusive branching ratios to be $(5.68 \pm 0.02)\times10^{-4} < BR(\overline{\Lambda}_{b} \rightarrow \overline{\mathrm{d}}+X) < (1.408 \pm 0.004)\times10^{-3}$ and $(7.4 \pm 0.3)\times10^{-6} < BR(B^{-} \rightarrow \overline{\mathrm{d}}+X < (4.34 \pm 0.07)\times10^{-5}$. The predicted rapidity- and transverse-momentum-differential yields populate the kinematic region where $\overline{\mathrm{d}}$ can be identified by the ALICE experiment, motivating dedicated searches for these decay channels. These results provide a quantitative benchmark for $\overline{\mathrm{d}}$ production from beauty-hadron decays and establish a phenomenological framework to support future experimental searches, with potential implications beyond collider physics.