Measurement of the flow harmonic correlations in pp, p+Pb and low multiplicity Pb+Pb collisions with the ATLAS detector at the LHC

Journal Article · 21 January 2019 · Nuclear Physics. A

DOI: https://doi.org/10.1016/j.nuclphysa.2018.09.076 · OSTI ID:1503106

Derendarz, Dominik  ^[1]

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1. Institute of Nuclear Physics PAS, Krakow (Poland)

Recent measurements of the correlations between flow harmonics obtained using four-particle symmetric cumulants and three-particle asymmetric cumulants with the ATLAS detector at the LHC are described. The data sets of pp, p+Pb and peripheral Pb+Pb collisions at various energies are analyzed, aiming to probe the long-range collective nature of multi-particle production in small systems. The sensitivity of the standard cumulant method to non-flow correlations is investigated by introducing the subevents method. A systematic reduction of non-flow effects is observed when using the two-subevent method. Further reduction is observed with the three-subevent method that is consistent with the results obtained with the four-subevent one. A negative correlation between ν₂ and ν₃ and a positive correlation between ν₂ and ν₄, for all studied collision systems and over full multiplicity range, is observed. The correlation strength computed as symmetric cumulants normalized by < v²_n >the is similar for all collision systems and weakly depends on multiplicity. In conclusion, these measurements provide new evidence for long-range multi-particle collectivity in small collision systems and quantify the nature of its event-by-event fluctuations.

• Research Organization: SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)
• Sponsoring Organization: USDOE
• Grant/Contract Number: AC02-76SF00515
• OSTI ID: 1503106
• Journal Information: Nuclear Physics. A, Journal Name: Nuclear Physics. A Journal Issue: C Vol. 982; ISSN 0375-9474
• Publisher: ElsevierCopyright Statement
• Country of Publication: United States
• Language: English