Abstract
The first measurement of the γ(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 γ(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 γ(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.
| Original language | English |
|---|---|
| Article number | 192301 |
| Journal | Physical Review Letters |
| Volume | 123 |
| Issue number | 19 |
| Number of pages | 13 |
| ISSN | 0031-9007 |
| DOIs | |
| Publication status | Published - 6 Nov 2019 |