The first measurement of the Υ(1S) elliptic flow coefficient (v2) is performed at forward rapidity (2.5 < y < 4) in Pb–Pb collisions at √sNN = 5.02 TeV with the ALICE detector at the LHC. The results are obtained with the scalar product method and are reported as a function of transverse momentum (pT ) up to 15 GeV=c in the 5%–60% centrality interval. The measured Υ(1S) v2 is consistent with 0 and with the small positive values predicted by transport models within uncertainties. The v2 coefficient in 2 < pT < 15 GeV=c is lower than that of inclusive J/ψ mesons in the same pT interval by 2.6 standard deviations. These results, combined with earlier suppression measurements, are in agreement with a scenario in which the Υ(1S) production in Pb–Pb collisions at LHC energies is dominated by dissociation limited to the early stage of the collision, whereas in the J=ψ case there is substantial experimental evidence of an additional regeneration component.

Measurement of γ(1S) Elliptic Flow at Forward Rapidity in Pb-Pb Collisions at √sNN =5.02 TeV

Camerini P.;Contin G.;Faggin M.;Lea R.;Luparello G.;Margagliotti G. V.;Piano S.;Rui R.;Zaccolo V.;
2019-01-01

Abstract

The first measurement of the Υ(1S) elliptic flow coefficient (v2) is performed at forward rapidity (2.5 < y < 4) in Pb–Pb collisions at √sNN = 5.02 TeV with the ALICE detector at the LHC. The results are obtained with the scalar product method and are reported as a function of transverse momentum (pT ) up to 15 GeV=c in the 5%–60% centrality interval. The measured Υ(1S) v2 is consistent with 0 and with the small positive values predicted by transport models within uncertainties. The v2 coefficient in 2 < pT < 15 GeV=c is lower than that of inclusive J/ψ mesons in the same pT interval by 2.6 standard deviations. These results, combined with earlier suppression measurements, are in agreement with a scenario in which the Υ(1S) production in Pb–Pb collisions at LHC energies is dominated by dissociation limited to the early stage of the collision, whereas in the J=ψ case there is substantial experimental evidence of an additional regeneration component.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11368/2954411
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