Flow Dominance and Factorization of Transverse Momentum Correlations in Pb-Pb Collisions at the LHC

(ALICE Collaboration)

Research output: Contribution to journalArticlepeer-review

11 Scopus citations

Abstract

We present the first measurement of the two-particle transverse momentum differential correlation function, P2≡ ΔpTΔpT/ pT2, in Pb-Pb collisions at sNN=2.76 TeV. Results for P2 are reported as a function of the relative pseudorapidity (Δη) and azimuthal angle (Δφ) between two particles for different collision centralities. The Δφ dependence is found to be largely independent of Δη for |Δη|≥0.9. In the 5% most central Pb-Pb collisions, the two-particle transverse momentum correlation function exhibits a clear double-hump structure around Δφ=π (i.e., on the away side), which is not observed in number correlations in the same centrality range, and thus provides an indication of the dominance of triangular flow in this collision centrality. Fourier decompositions of P2, studied as a function of the collision centrality, show that correlations at |Δη|≥0.9 can be well reproduced by a flow ansatz based on the notion that measured transverse momentum correlations are strictly determined by the collective motion of the system.

Original languageEnglish
Article number162302
JournalPhysical Review Letters
Volume118
Issue number16
DOIs
StatePublished - Apr 21 2017

Funding

FundersFunder number
Not addedST/P004598/1, ST/P005438/1
National Science Foundation1307461
Horizon 2020 Framework Programme665779
Science and Technology Facilities CouncilST/M001601/1, 2017 STFC Nuclear Physics CG, GRIDPP, ST/L005670/1, 2014 STFC Nuclear Physics CG, ST/N00261X/1, 1657698, ALICE, ST/M00340X/1, ST/L005751/1, ST/J000108/1, ST/M00158X/1, ST/M001598/1
Japan Society for the Promotion of Science15H03664, 17H01122

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