engleski

Υ suppression at forward rapidity in Pb-Pb collisions at √sNN = 5.02 TeV

Inclusive ϒ(1S) and ϒ(2S) production have been measured in Pb– Pb collisions at the centre-of- mass energy per nucleon– nucleon pair √sNN=5.02 TeV, using the ALICE detector at the CERN LHC. The ϒ mesons are reconstructed in the centre- of- mass rapidity interval y<2.5, 4> and in the transverse- momentum range pT<15 GeV/ c , via their decays to muon pairs. In this Letter, we present results on the inclusive ϒ(1S) nuclear modification factor RAA as a function of collision centrality, transverse momentum and rapidity. The ϒ(1S) and ϒ(2S) RAA , integrated over the centrality range 0–90%, are 0.37±0.02(stat)±0.03(syst) and 0.10±0.04(stat) ±0.02(syst) , respectively, leading to a ratio RAAϒ(2S)/RAAϒ(1S) of 0.28±0.12(stat)±0.06(syst) . The observed ϒ(1S) suppression increases with the centrality of the collision and no significant variation is observed as a function of transverse momentum and rapidity.

heavy ion: scattering ; muon: pair ; rapidity ; transverse momentum ; suppression ; nucleon nucleon ; CERN LHC Coll ; CERN Lab ; nucleus ; ALICE ; meson

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