Effects of triangular flow on di-hadron azimuthal correlations in relativistic heavy ion collisions

Using the AMPT model for relativistic heavy ion collisions, we have studied the di-hadron azimuthal angular correlations triggered by emitted jets in $\text{Au}+\text{Au}$ collisions at center-of-mass energy $\sqrt{s_{\mathit{NN}}}=200$ GeV and impact parameter $b=8$ fm. A double-peak structure for the associated particles at the away side of trigger particles is obtained after subtracting background correlations due to the elliptic flow. Both the near-side peak and the away-side double peaks in the azimuthal angular correlations are, however, significantly suppressed (enhanced) in events of small (large) triangular flow or triangularity in the initial collision geometry as a result of fluctuations. After subtraction of background correlations due to the triangular flow, the away-side double peaks change into a single peak with broad shoulders on both sides. The away side of the di-hadron correlations becomes essentially a single peak after further subtraction of higher-order flows.

Figure 1

Event distributions of elliptic flow $v_2$ and triangular flow $v_3$ (a) and corresponding event plane angles ${\psi }_2$ and ${\psi }_3$ (b) in $\text{Au}+\text{Au}$ collisions at $\sqrt{s_{\mathit{NN}}}=200$ GeV and $b=8$ fm from the AMPT model.

Figure 2

Transverse momentum dependence of the hadron elliptic ($v_2$) and triangular ($v_3$) flows.

Figure 3

Di-hadron azimuthal angular correlations per trigger particle before (a) and after (b) subtracting background correlations due to the hadron elliptic flow shown by the dashed line in panel (a).

Figure 4

(a) The triangular flow $v_3$ as a function of transverse momentum and (b) di-hadron azimuthal angular correlations per trigger particle from all events and from events of small or large triangular flow.

Figure 5

Di-hadron azimuthal angular correlations per trigger particle before (a) and after subtracting background correlations due to both hadron elliptic and triangular flows (b) shown by the dashed line in panel (a) and due to anisotropic flows up to the fifth order (c) shown by the dotted line in panel (a).