Harmonic decomposition of three-particle azimuthal correlations at energies available at the BNL Relativistic Heavy Ion Collider

Abstract

We present measurements of three-particle correlations for various harmonics in Au+Au collisions at energies ranging from $\sqrt{{s}_{\mathrm{NN}}}=7.7$ to 200 GeV using the STAR detector. The quantity $\ensuremath{\langle}cos(m{\ensuremath{\phi}}_{1}+n{\ensuremath{\phi}}_{2}\ensuremath{-}(m+n){\ensuremath{\phi}}_{3})\ensuremath{\rangle}$, with $\ensuremath{\phi}$ being the azimuthal angles of the particles is evaluated as a function of $\sqrt{{s}_{\mathrm{NN}}}$, collision centrality, transverse momentum, ${p}_{T}$, pseudorapidity difference, $\mathrm{\ensuremath{\Delta}}\ensuremath{\eta}$, and harmonics ($m$ and $n$). These data provide detailed information on global event properties such as the three-dimensional structure of the initial overlap region, the expansion dynamics of the matter produced in the collisions, and the transport properties of the medium. A strong dependence on $\mathrm{\ensuremath{\Delta}}\ensuremath{\eta}$ is observed for most harmonic combinations, which is consistent with breaking of longitudinal boost invariance. An interesting energy dependence is observed when one of the harmonics $m,n,$ or $m+n$ is equal to two, for which the correlators are dominated by the two-particle correlations relative to the second-harmonic event plane. These measurements can be used to constrain models of heavy-ion collisions over a wide range of temperature and baryon chemical potential.