Measurements of the anisotropic flow coefficients $v_2\left\{{\mathrm{\Psi }}_2\right\},v_3\left\{{\mathrm{\Psi }}_3\right\},v_4\left\{{\mathrm{\Psi }}_4\right\}$, and $v_4\left\{{\mathrm{\Psi }}_2\right\}$ for identified particles (${\pi }^{\pm },K^{\pm }$, and $p+\overline{p}$) at midrapidity, obtained relative to the event planes ${\mathrm{\Psi }}_m$ at forward rapidities in Au + Au collisions at $\sqrt{s_{{}_{NN}}}=200\mathrm{GeV}$, are presented as a function of collision centrality and particle transverse momenta $p_T$. The $v_n$ coefficients show characteristic patterns consistent with hydrodynamical expansion of the matter produced in the collisions. For each harmonic $n$, a modified valence quark-number $N_q$ scaling [plotting $v_n\left\{{\mathrm{\Psi }}_m\right\}/{\left(N_q\right)}^{n/2}$ versus transverse kinetic energies $\left({\mathrm{KE}}_T\right)/N_q]$ is observed to yield a single curve for all the measured particle species for a broad range of ${\mathrm{KE}}_T$. A simultaneous blast-wave model fit to the observed $v_n\left\{{\mathrm{\Psi }}_m\right\}\left(p_T\right)$ coefficients and published particle spectra identifies radial flow anisotropies ${\rho }_n\left\{{\mathrm{\Psi }}_m\right\}$ and spatial eccentricities $s_n\left\{{\mathrm{\Psi }}_m\right\}$ at freeze-out. These are generally smaller than the initial-state participant-plane geometric eccentricities ${\varepsilon }_n\left\{{\mathrm{\Psi }}_m^{\mathrm{PP}}\right\}$ as also observed in the final eccentricity from quantum interferometry measurements with respect to the event plane.

• Received 3 December 2014
• Revised 13 July 2015

DOI:https://doi.org/10.1103/PhysRevC.93.051902