Speaker
Description
The triangular flow coefficient ($v_{3}$) is the third term in the Fourier expansion of the azimuthal distribution of particles produced in heavy-ion collisions. A non-zero $v_{3}$ arises from event-by-event fluctuations in the positions of participant nucleons within the collision zone. Higher order flow coefficients, particularly $v_{3}$ and higher harmonics, exhibit enhanced sensitivity to the transport properties of the created medium, including the shear viscosity-to-entropy density ratio ($\eta/s$) [1].
In this talk, we present the measurement of $v_{3}$ for identified hadrons in Au+Au collisions from the RHIC Beam Energy Scan (BES) by the STAR experiment, covering $\sqrt{s_{NN}} = 7.7$ to $62.4$ GeV. We will show the transverse momentum ($p_{T}$), centrality, and collision energy dependence of $v_{3}$, which serve as important observables for constraining the $\eta/s$ of the medium. Additionally, we will present the number-of-constituent-quark (NCQ) scaling and the coalescence sum rule for $v_{3}$, which may provide insight into the properties of the medium and the possible onset or disappearance of partonic collectivity.
[1] Björn Schenke, Sangyong Jeon and Charles Gale, Phys. Rev. C. 85, 024901 (2012).
