NCQ scaling of $f_{0}(980)$ elliptic flow in 200 GeV Au+Au collisions by STAR and its constituent quark content

Abstract

Searching for exotic state particles and studying their properties have furthered our understanding of quantum chromodynamics (QCD). The $f_{0}$(980) resonance is an exotic state with relatively high production rate in relativistic heavy-ion collisions, decaying primarily into $\pi\pi$. Currently, the structure and quark content of the $f_{0}$(980) are unknown with several predictions from theory being a $q\overline{q}$ state, a $qq\overline{q}\overline{q}$ state, a $K\overline{K}$ molecule state, or a gluonium state. We report the first $f_{0}$(980) elliptic flow ($v_{2}$) measurement from 200 GeV Au+Au collisions at STAR. The transverse momentum dependence of $v_{2}$ is examined and compared to those of other hadrons (baryons and mesons). The empirical number of constituent quark (NCQ) scaling is used to investigate the constituent quark content of $f_{0}$(980), which may potentially address an important question in QCD.