Measurements of the suppression and correlations of dijets in Xe+Xe collisions at $\sqrt{s_{NN}}$ = 5.44 TeV

The ATLAS collaboration
Phys.Rev.C 108 (2023) 024906, 2023.

Abstract (data abstract)
A measurement of the suppression and correlations of dijets is performed using 3~$\mu$b$^{-1}$ of Xe+Xe data at $\sqrt{s_{\mathrm{NN}}} = 5.44$~TeV collected with the ATLAS detector at the LHC. Dijets with jets reconstructed using the $R=0.4$ anti-$k_t$ algorithm are measured differentially in jet $p_{\text{T}}$ over the range of 32~GeV to 398~GeV and centrality of the collision. Significant dijet momentum imbalance is found in the most central Xe+Xe collisions, which decreases in more peripheral collisions. Results from the measurement of per-pair normalized and absolutely normalized dijet $p_{\text{T}}$ balance are compared with previous Pb+Pb measurement at $\sqrt{s_{\mathrm{NN}}} =5.02$~TeV. The differences between the dijet suppression in Xe+Xe and Pb+Pb are further quantified by the ratio of pair nuclear modification factors. The results are found to be consistent with those measured in Pb+Pb data when compared in classes of the same event activity and when taking into account the difference in the centre-of-mass energy of the initial parton scattering process between Xe+Xe and Pb+Pb collisions. These results provide a better understanding of the role of energy density, system size, path-length, and fluctuations in the parton energy loss.

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