Measurement of flow harmonics correlations with mean transverse momentum in lead–lead and proton–lead collisions at s NN = 5.02 TeV with the ATLAS detector


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Authors
Aad, G. 
Abbott, B. 
Abbott, D. C. 
Abud, A. Abed 
Abeling, K. 
Abstract

Abstract: To assess the properties of the quark–gluon plasma formed in ultrarelativistic ion collisions, the ATLAS experiment at the LHC measures a correlation between the mean transverse momentum and the flow harmonics. The analysis uses data samples of lead–lead and proton–lead collisions obtained at the centre-of-mass energy per nucleon pair of 5.02 TeV, corresponding to total integrated luminosities of 22μb-1 and 28nb-1, respectively. The measurement is performed using a modified Pearson correlation coefficient with the charged-particle tracks on an event-by-event basis. The modified Pearson correlation coefficients for the 2nd-, 3rd-, and 4th-order flow harmonics are measured in the lead–lead collisions as a function of event centrality quantified as the number of charged particles or the number of nucleons participating in the collision. The measurements are performed for several intervals of the charged-particle transverse momentum. The correlation coefficients for all studied harmonics exhibit a strong centrality evolution, which only weakly depends on the charged-particle momentum range. In the proton–lead collisions, the modified Pearson correlation coefficient measured for the 2nd-order flow harmonics shows only weak centrality dependence. The lead-lead data is qualitatively described by the predictions based on the hydrodynamical model.

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Keywords
Regular Article - Experimental Physics
Journal Title
The European Physical Journal C
Conference Name
Journal ISSN
1434-6044
1434-6052
Volume Title
79
Publisher
Springer Berlin Heidelberg