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.
Original language | English |
---|---|
Article number | 192301 |
Journal | Physical Review Letters |
Volume | 123 |
Issue number | 19 |
DOIs | |
Publication status | Published - 2019 |
Subject classification (UKÄ)
- Subatomic Physics
Free keywords
- Atomic physics
- Physics
- Experimental evidence
- Forward rapidity
- Pb-Pb collisions
- Positive value
- Scalar product
- Standard deviation
- Transport models
- Transverse momenta
- Binary alloys