Production of the ρ(770)0 meson in pp and Pb-Pb collisions at √sNN = 2.76 TeV

Abstract

The production of the ρ ( 770 ) 0 meson has been measured at midrapidity ( | y | < 0.5 ) in p p and centrality differential Pb-Pb collisions at √ s N N = 2.76 TeV with the ALICE detector at the Large Hadron Collider. The particles have been reconstructed in the ρ ( 770 ) 0 → π + π − decay channel in the transverse-momentum ( p T ) range 0.5–11 GeV / c . A centrality-dependent suppression of the ratio of the integrated yields 2 ρ ( 770 ) 0 / ( π + + π − ) is observed. The ratio decreases by ∼ 40 % from p p to central Pb-Pb collisions. A study of the p T -differential 2 ρ ( 770 ) 0 / ( π + + π − ) ratio reveals that the suppression occurs at low transverse momenta, p T < 2 GeV / c . At higher momentum, particle ratios measured in heavy-ion and p p collisions are consistent. The observed suppression is very similar to that previously measured for the K ∗ ( 892 ) 0 / K ratio and is consistent with EPOS3 predictions that may imply that rescattering in the hadronic phase is a dominant mechanism for the observed suppression.