Beam-energy dependence of the directed flow of deuterons in Au+Au collisions

The collaboration
Phys.Rev.C 102 (2020) 044906, 2020.

Abstract
We present a measurement of the first-order azimuthal anisotropy, $v_1(y)$, of deuterons from Au+Au collisions at $\sqrt{s_{NN}}$ = 7.7, 11.5, 14.5, 19.6, 27, and 39 GeV recorded with the STAR experiment at the Relativistic Heavy Ion Collider (RHIC). The energy dependence of the $v_1(y)$ slope, $dv_{1}/dy|_{y=0}$, for deuterons, where $y$ is the rapidity, is extracted for semi-central collisions (10-40\% centrality) and compared to that of protons. While the $v_1(y)$ slopes of protons are generally negative for $\sqrt{s_{NN}} >$ 10 GeV, those for deuterons are consistent with zero, a strong enhancement of the $v_1(y)$ slope of deuterons is seen at the lowest collision energy (the largest baryon density) at $\sqrt{s_{NN}} =$ 7.7 GeV. In addition, we report the transverse momentum dependence of $v_1$ for protons and deuterons. The experimental results are compared with transport and coalescence models.

• #### Fig3

Data from Fig. 3

10.17182/hepdata.95544.v1/t1

The 1st-order event plane ($\Psi_{1}$) resolution as a function of centrality of Au+Au collisions at $\sqrt{s_{NN}}$ = 7.7, 11.5, 14.5,...

• #### Fig4_proton

Data from Fig. 4 (open squares)

10.17182/hepdata.95544.v1/t2

Rapidity dependene of $v_1$ for protons(open squares) in 10-40 \%Au+Au collisions at $\sqrt{s_{NN}}$ = 7.7, 11.5, 14.5, 19.6, 27, and...

• #### Fig4_deuteron

Data from Fig. 4 (solid circles)

10.17182/hepdata.95544.v1/t3

Rapidity dependene of $v_1$ for deuterons(solid circles) in 10-40 \%Au+Au collisions at $\sqrt{s_{NN}}$ = 7.7, 11.5, 14.5, 19.6, 27, and...

• #### Fig5

Data from Fig. 5

10.17182/hepdata.95544.v1/t4

Directed flow slope at mid-rapidity, $dv_{1}/dy|_{y=0}$, as a function of beam energy in 10-40\% Au+Au collisions. Dots represent deuterons. Open...

• #### Fig6_proton

Data from Fig. 6 (open squares)

10.17182/hepdata.95544.v1/t5

The $p_{T}$ dependence of $v_1/A$ in $|y|<0.6$ for protons (open squares) in 10-40\% Au+Au collisions at $\sqrt{s_{NN}}$ = 7.7, 11.5,...

• #### Fig6_deuteron

Data from Fig. 6 (solid circles)

10.17182/hepdata.95544.v1/t6

The $d_{T}$ dependence of $v_1/A$ in $|y|<0.6$ for deuterons (solid circles) in 10-40\% Au+Au collisions at $\sqrt{s_{NN}}$ = 7.7, 11.5,...