Speaker
Description
At the LHC, matter and antimatter are produced in equal abundance, making it a true antimatter factory. Among the many antiparticles observed, antinuclei are of particular interest, as their production mechanism in high-energy hadronic collisions remains a topic of active discussion and fascination. The ALICE Collaboration has previously measured, for the first time, the production of anti-alpha ($\overline{^4\mathrm{He}}$) nuclei in pp and Pb–Pb collisions. However, $^4$He isnot the only known A = 4 nucleus: the unstable $^4$Li nucleus has also been observed in a few experiments and is experimentally accessible by ALICE. In this talk, the first evidence of the antimatter counterpart of $^4$Li, the anti-$^4$Li nucleus ($\overline{^4\mathrm{Li}}$), is presented. The particle is reconstructed via its two-body decay channel $\overline{^4\mathrm{Li}} \rightarrow \overline{^3\mathrm{He}}$+p, using both invariant-mass analysis and femtoscopic correlations.
A dedicated analysis procedure has been developed to subtract the correlated and uncorrelated $\overline{^3\mathrm{He}}-\overline{\mathrm p}$ combinatorial background. The production yield of $\overline{^4\mathrm{Li}} $ is compared with that of $\overline{^4\mathrm{He}}$. Owing to its resonance nature and its spin degeneracy, the production of $\overline{^4\mathrm{Li}}$ is expected to be enhanced relative to the compact $\overline{^4\mathrm{He}}$, making this new measurement a sensitive probe for testing nucleosynthesis models in high-energy hadronic collisions.
