3ΛH and 3Λ¯ production in Pb–Pb collisions at √sNN = 2.76 TeV

Abstract

The production of the hypertriton nuclei 3ΛH and 3Λ¯ has been measured for the first time in Pb–Pb collisions at √sNN = 2.76 TeV with the ALICE experiment at LHC. The pT-integrated 3 !H yield in one unity of rapidity, dN/dy × B.R. ! 3 !H→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 !H/(3He×!/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 measured 3 !H lifetime, τ = 181+54 −39 (stat.) ± 33(syst.) ps is in agreement within 1σ with the world average value.