Suppression of $\Lambda(1520)$ resonance production in central Pb-Pb collisions at $\sqrt{s_{\rm NN}}$ = 2.76 TeV

The production yield of the Λ(1520) baryonresonance is measured at midrapidity in Pb-Pb collisionsat sNN = 2.76 TeV with the ALICE detector at the Large Hadron Collider(LHC). The measurement is performed in the Λ(1520)→pK− (and charge conjugate) hadronicdecay channel as a function of the transverse momentum (pT) and collisioncentrality. The ratio of the pT- integrated productionof Λ(1520) baryonsrelative to Λ baryonsin central collisionsis suppressed by about a factor of 2 with respect to peripheral collisions. This is the first observation of the suppression of a baryonicresonance at the LHC and the first 3σ evidence of Λ(1520) suppression within a single collisionsystem. The measured Λ(1520)/Λ ratio in central collisionsis smaller than the value predicted by the statistical hadronizationmodel calculations. The shape of the measured pT distribution and the centrality dependence of the suppression are reproduced by the EPOS3 Monte Carlo event generator. The measurement adds further support to the formation of a dense hadronicphase in the final stages of the evolution of the fireball created in heavy-ion collisions, lasting long enough to cause a significant reduction in the observable yield of short-lived resonances.