Antinuclei from $\overline{\Lambda}_{b}$ decays

Light antinuclei in space such as antideuterons and antihelium-3 are considered as one of the most promising probes for indirect dark-matter searches, because astrophysical production via convenient Standard Model processes is expected to be extremely low. Recent observations by the Alpha Mag- netic Spectrometer of a handful of tentative antihelium events have triggered a lot of discussions about their potential origin. Among them the production of antihelium through the decays of $\overline{\Lambda}_{b}$ baryons was demonstrated to be able to significantly boost the antihelium flux in space. However, the branching ratio of $\overline{\Lambda}_{b}$ $\rightarrow $ $\overline{^3He}$+ X process is not known from the experiment, which can signif- icantly affect the resulting antihelium flux. In this project, we use the ALICE detector capabilities to search for the antihelium nuclei from displaced vertex of $\overline{\Lambda}_{b}$ decays with the Run 3 pp data. The distance of closest approach of antihelium nuclei is fitted with various templates that include the $\overline{\Lambda}_{b}$ $\rightarrow $ $\overline{^3He}$+ X , which can be used to directly constrain the inclusive $\overline{\Lambda}_{b}$ $\rightarrow $ $\overline{^3He}$+ X branching ratio. The analysis techniques are first validated and tested by looking at the antideuteron nuclei that can also come from the decays of Λb baryon.