³_ΛH and ³_Λ̅H̅ production in Pb–Pb collisions at √s_NN = 2.76 TeV

The production of the hypertriton nuclei ³_ΛH and ³_Λ̅H̅ has been measured for the first time in Pb–Pb collisions at √s_NN = 2.76 TeV with the ALICE experiment at LHC. The p_T-integrated ³_ΛH yield in one unity of rapidity, dN/dy × B . R . ( ³_ΛH → ³He, π⁻) = (3.86±0.77(stat.)±0.68(syst.) ) × 10⁻⁵ in the 0–10% most central collisions, is consistent with the predictions from a statistical thermal model using the same temperature as for the light hadrons. The coalescence parameter B₃ shows a dependence on the transverse momentum, similar to the B₂ of deuterons and the B₃ of ³He nuclei. The ratio of yields S₃ = ³_ΛH/( ³He × Λ/p) was measured to be S₃ = 0.60±0.13( stat. )±0.21(syst.) in 0–10% centrality events; this value is compared to different theoretical models. The measured S₃ is compatible with thermal model predictions. The measured³_ΛH lifetime, τ = 181₋₃₉₊₅₄ (stat.)±33(syst.) ps is in agreement within 1σ with the world average value.