Charged-particle angular correlations in XeXe collisions at $\sqrt{s_{_\mathrm{NN}}}=$ 5.44 TeV

The collaboration
Phys.Rev.C 100 (2019) 044902, 2019.

Abstract (data abstract)
Azimuthal correlations of charged particles in xenon-xenon collisions at a center-of-mass energy per nucleon pair of $\sqrt{s_{_\mathrm{NN}}} = 5.44~$TeV are studied. The data were collected by the CMS experiment at the LHC with a total integrated luminosity of $3.42~\mathrm{\mu b}^{-1}$. The collective motion of the system formed in the collision is parameterized by a Fourier expansion of the azimuthal particle density distribution. The azimuthal anisotropy coefficients $v_{2}$, $v_{3}$, and $v_{4}$ are obtained by the scalar-product, two-particle correlation, and multiparticle correlation methods. Within a hydrodynamic picture, these methods have different sensitivities to non-collective and fluctuation effects. The dependence of the Fourier coefficients on the size of the colliding system is explored by comparing the xenon-xenon results with equivalent lead-lead data. Model calculations that include initial-state fluctuation effects are also compared to the experimental results. The observed angular correlations provide new constraints on the hydrodynamic description of heavy ion collisions.