A new, more precise measurement of the Λ hyperon lifetime is performed using a large data sample of Pb–Pb collisions at √s NN = 5.02 TeV with ALICE. The Λ and antiΛ hyperons are reconstructed at midrapidity using their two-body weak decay channel Λ → p þ π− and antiΛ → antip + π+. The measured value of the Λ lifetime is τΛ=[261.07 +/- 0.37 (stat) +/- 0.72 (syst)] ps. The relative difference between the lifetime of Λ and antiΛ, which represents an important test of CPT invariance in the strangeness sector, is also measured. The obtained value (τΛ− τantiΛ)/τΛ = 0.0013 +/- 0.0028 (stat) +/- 0.0021 (syst) is consistent with zero within the uncertainties. Both measurements of the Λ hyperon lifetime and of the relative difference
between τΛ and τantiΛ are in agreement with the corresponding world averages of the Particle Data Group and about a factor of three more precise.
