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

The production of K∗(892)0 and ϕ(1020) mesons in proton-proton (pp) and lead-lead (Pb-Pb) collisions at √sNN=2.76TeV has been analyzed using a high luminosity data sample accumulated in 2011 with the ALICE detector at the Large Hadron Collider (LHC). Transverse momentum (pT) spectra have been measured for K∗(892)0 and ϕ(1020) mesons via their hadronic decay channels for pT up to 20GeV/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≈3GeV/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.

kaon, proton-proton, high transverse momentum

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