Measurement of multi-particle azimuthal correlations in pp, p + Pb and low-multiplicity Pb + Pb collisions with the ATLAS detector

Summary, in English

Multi-particle cumulants and corresponding Fourier harmonics are measured for azimuthal angle distributions of charged particles in pp collisions at s = 5.02 and 13 TeV and in p + Pb collisions at sNN = 5.02 TeV, and compared to the results obtained for low-multiplicity Pb+Pb collisions at sNN = 2.76 TeV. These measurements aim to assess the collective nature of particle production. The measurements of multi-particle cumulants confirm the evidence for collective phenomena in p + Pb and low-multiplicity Pb+Pb collisions. On the other hand, the pp results for four-particle cumulants do not demonstrate collective behaviour, indicating that they may be biased by contributions from non-flow correlations. A comparison of multi-particle cumulants and derived Fourier harmonics across different collision systems is presented as a function of the charged-particle multiplicity. For a given multiplicity, the measured Fourier harmonics are largest in Pb+Pb, smaller in p + Pb and smallest in pp collisions. The pp results show no dependence on the collision energy, nor on the multiplicity. © 2017, CERN for the benefit of the ATLAS collaboration.

• Author: M Aaboud; G Aad; B. Abbott; J Abdallah; O Abdinov; B Abeloos; Torsten Åkesson; Simona Bocchetta; Caterina Doglioni; Vincent Hedberg; Göran Jarlskog; Charles Kalderon; Else Lytken; Ulf Mjörnmark; Trine Poulsen; Oxana Smirnova; Oleksandr Viazlo
• Department/s: Particle and nuclear physics; eSSENCE: The e-Science Collaboration
• Publishing year: 2017
• Language: English
• Publication/Series: European Physical Journal C
• Volume: 77
• Issue: 6
• Links: http://dx.doi.org/10.1140/epjc/s10052-017-4988-1
• Document type: Journal article
• Publisher: Springer Nature
• Topic: Subatomic Physics
• Status: Published
• ISBN/ISSN/Other: ISSN: 1434-6044