The first measurement of the Upsilon(1S) elliptic flow coefficient (v(2)) is performed at forward rapidity (2.5 < y < 4) in Pb-Pb collisions at root s(NN) = 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 Upsilon(1S)v(2) is consistent with 0 and with the small positive values predicted by transport models within uncertainties. The v(2) coefficient in 2 < p(T) < 15 GeV=c is lower than that of inclusive J/psi mesons in the same p(T) interval by 2.6 standard deviations. These results, combined with earlier suppression measurements, are in agreement with a scenario in which the Upsilon(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/psi case there is substantial experimental evidence of an additional regeneration component.

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

Mastroserio, A.;
2019-01-01

Abstract

The first measurement of the Upsilon(1S) elliptic flow coefficient (v(2)) is performed at forward rapidity (2.5 < y < 4) in Pb-Pb collisions at root s(NN) = 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 Upsilon(1S)v(2) is consistent with 0 and with the small positive values predicted by transport models within uncertainties. The v(2) coefficient in 2 < p(T) < 15 GeV=c is lower than that of inclusive J/psi mesons in the same p(T) interval by 2.6 standard deviations. These results, combined with earlier suppression measurements, are in agreement with a scenario in which the Upsilon(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/psi 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/11369/450359
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