Speaker
Description
Recent measurements on collectivity of charged hadrons in both asymmetric and symmetric small collision systems have far-reaching implications on the origins of final state momentum anisotropy driven by nucleonic as well as sub-nucleonic degrees of freedom present during initial state. During the data taking in 2021, STAR had recorded large statistics of minimum bias and high multiplicity events of O+O collisions at $\sqrt{s_{\text{NN}}} = 200$ GeV. We present the first measurements of anisotropic flow of strange and multi-strange hadrons in O+O collisions. These hadrons are considered as good probes for initial state dynamics given their production at the early stages of medium evolution. In particular, we study the transverse momentum ($p_{\text{T}}$) and centrality dependence of elliptic ($v_2$) and triangular ($v_3$) flow of $\text{K}^0_{\text{S}},\, \Lambda+\overline{\Lambda}$ and $\phi$. System size dependence of the same is also shown by comparing with existing measurements of strange hadron collectivity in relatively larger systems (such as Cu+Cu, Au+Au and U+U) at the same collision energy. Formation of Quark-Gluon Plasma (QGP) in small collision systems has long been argued given their extremely short lifetime. In this regard, we test the number-of-constituent-quark (NCQ) scaling hypothesis for strange hadron $v_2$ and $v_3$ in central O+O collisions to understand the influence of partonic phase on the origins of collectivity.
