K∗(892)0 and ϕ(1020) meson production at high transverse momentum in pp and Pb-Pb collisions at √sNN=2.76 TeV

Abstract

The production of K∗ ( 892 ) 0 and ϕ ( 1020 ) mesons in proton-proton ( p p ) and lead-lead (Pb-Pb) collisions at √ s NN = 2.76 TeV has been analyzed using a high luminosity data sample accumulated in 2011 with the ALICE detector at the Large Hadron Collider (LHC). Transverse momentum ( p T ) spectra have been measured for K∗ ( 892 ) 0 and ϕ ( 1020 ) mesons via their hadronic decay channels for pT up to 20 GeV / c . The measurements in pp collisions have been compared to model calculations and used to determine the nuclear modification factor and particle ratios. The K∗ ( 892 ) 0 / K ratio exhibits significant reduction from pp to central Pb-Pb collisions, consistent with the suppression of the K∗ ( 892 ) 0 yield at low pT due to rescattering of its decay products in the hadronic phase. In central Pb-Pb collisions the pT dependent ϕ ( 1020 ) / π and K∗ ( 892 ) 0 / π ratios show an enhancement over pp collisions for pT≈ 3 GeV / c , consistent with previous observations of strong radial flow. At high pT, particle ratios in Pb-Pb collisions are similar to those measured in pp collisions. In central Pb-Pb collisions, the production of K∗ ( 892 ) 0 and ϕ ( 1020 ) mesons is suppressed for pT>8GeV / c . This suppression is similar to that of charged pions, kaons, and protons, indicating that the suppression does not depend on particle mass or flavor in the light quark sector.