Abstract (data abstract)

CERN-LHC. The production yield of the $\Lambda$(1520) baryon resonance is measured at mid-rapidity in Pb-Pb collisions at $\sqrt{s_{\rm NN}}$ = 2.76 TeV with the ALICE detector at the LHC. The measurement is performed in the $\Lambda$(1520) $\to$ p K$^{-}$ (and charge conjugate) hadronic decay channel as a function of the transverse momentum ($p_{\rm T}$) and collision centrality. The $p_{\rm T}$-integrated production rate of $\Lambda$(1520) relative to $\Lambda$ in central collisions is suppressed by about a factor of 2 with respect to peripheral collisions. This is the first observation of the suppression of a baryonic resonance at LHC and the first evidence of $\Lambda$(1520) suppression in heavy-ion collisions. The measured $\Lambda$(1520)/$\Lambda$ ratio in central collisions is smaller than the value predicted by the statistical hadronisation model calculations. The shape of the measured $p_{\rm T}$ 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 hadronic phase 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.

Table 1

10.17182/hepdata.84284.v1/t1

$p_{\rm T}$-differential yields of $\Lambda$(1520) (sum of particle and anti-particle states) at midrapidity in the 0-20% centrality class. The uncertainty...
Table 2

10.17182/hepdata.84284.v1/t2

$p_{\rm T}$-differential yields of $\Lambda$(1520) (sum of particle and anti-particle states) at midrapidity in the 20-50% centrality class. The uncertainty...
Table 3

10.17182/hepdata.84284.v1/t3

$p_{\rm T}$-differential yields of $\Lambda$(1520) (sum of particle and anti-particle states) at midrapidity in the 50-80% centrality class. The uncertainty...
Table 4

10.17182/hepdata.84284.v1/t4

$\langle p_{\rm T} \rangle$ of $\Lambda$(1520) (sum of particle and anti-particle states) at midrapidity as a function of $\langle {\rm...
Table 5

10.17182/hepdata.84284.v1/t5

$\Lambda$(1520) (sum of particle and anti-particle states) to $\Lambda$ (defined as 2 $\Lambda$) $p_{\rm T}$-integrated yield ratio at midrapidity as...

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