Proton, deuteron and triton flow measurements in Au+Au collisions at $\sqrt{s_{NN}}=2.4$ GeV

Abstract

High precision measurements of flow coefficients $v_n$ ($n=1-4$) for protons, deuterons and tritons relative to the first-order spectator plane have been performed in Au+Au collisions at $\sqrt{s_{NN}}=2.4$ GeV with the High-Acceptance Di-Electron Spectrometer (HADES) at the SIS18/GSI. Flow coefficients are studied as a function of transverse momentum $p_t$ and rapidity $y_{cm}$ over a large region of phase space and for several classes of collision centrality. A clear mass hierarchy is found for the slope of $v_1$, $d{v}_1/d{y}^{\prime }{|}_{y^{\prime }=0}$ where $y^{\prime }$ is the scaled rapidity, and for $v_2$ at mid-rapidity. Scaling with the number of nucleons is observed for the $p_t$ dependence of $v_2$ and $v_4$ at mid-rapidity, which is indicative for nuclear coalescence as the main process responsible for light nuclei formation. $v_2$ is found to scale with the initial eccentricity $⟨{\epsilon }_2⟩$, while $v_4$ scales with $⟨{\epsilon }_2{⟩}^2$ and $⟨{\epsilon }_4⟩$. The multi-differential high-precision data on $v_1$, $v_2$, $v_3$, and $v_4$ provides important constraints on the equation-of-state of compressed baryonic matter.

21 pages, 18 figures, 4 tables; Figs. 11 updated; The manuscript has associated data in the HEPData repository: https://doi.org/10.17182/hepdata.152804