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

Summary, in English

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.

• Author: S Acharya; Jonatan Adolfsson; Peter Christiansen; Oliver Matonoha; Adrian Nassirpour; Anders Oskarsson; Tuva Richert; Omar Vazquez Rueda; David Silvermyr; Evert Stenlund; N Zurlo
• Department/s: Particle and nuclear physics; eSSENCE: The e-Science Collaboration
• Publishing year: 2019
• Language: English
• Publication/Series: Physical Review Letters
• Volume: 123
• Issue: 19
• Links: http://dx.doi.org/10.1103/PhysRevLett.123.192301
• Document type: Journal article
• Publisher: American Physical Society
• Topic: Subatomic Physics
• Keywords: Atomic physics; Physics; Experimental evidence; Forward rapidity; Pb-Pb collisions; Positive value; Scalar product; Standard deviation; Transport models; Transverse momenta; Binary alloys
• Status: Published
• ISBN/ISSN/Other: ISSN: 1079-7114