Abstract
One of the most effective ways to investigate quark–gluon plasma (QGP) properties is to measure the azimuthal particle anisotropy in momentum space. This anisotropy can be characterized by the elliptic flow ( \(v_{2}\) ). The evolution of the elliptic flow can be studied by using these two approaches: either measure \(v_{2}\) values in different collision systems or use different particles of interest. Varying collision systems allows to investigate the impact of initial conditions on \(v_{2}\) values. Also, using small-system collisions provides the opportunity to measure \(v_{2}\) values in low multiplicity regions, where the conditions for QGP formation may be unachievable. Neutral pion is considered a unique tool to study \(v_{2}\) development mechanisms, because its yields are measurable up to large transverse momenta ( \(p_{T}\) ) in small and large collision systems, where different effects of \(v_{2}\) development can dominate. This work is dedicated to the measurement of the \(v_{2}\) values for \(\pi^{0}\) mesons as a function of \(p_{T}\) and centrality in small collision system— \({}^{3}\) He \(+\) Au, and the largest collision system at RHIC—U \(+\) U.
