Elliptic flow of resonances in relativistic heavy ion collisions: Probing final state interactions and the structure of resonances

We propose the measurement of the elliptic flow of hadron resonances at the Relativistic Heavy Ion Collider as a tool to probe the amount of hadronic final state interactions for resonances at intermediate and large transverse momenta. This can be achieved by looking at systematic deviations of the measured flow coefficient $v_2$ from the scaling law given by the quark recombination formalism. Our method can be generalized to explore the structure of exotic particles, such as the recently found pentaquark ${\Theta }^{+}\left(1540\right)$.

Figure 1

(Color online) Elliptic flow $v_2$ as a function of $P_T$ for ${\Sigma }^{*}\left(1385\right)$ (top) and $K_0^{*}\left(892\right)$ (bottom). Dashed line: resonance contribution from hadronization (QGP); dotted line: resonance contribution from coalescence in a hadron gas (HG); solid line: calculation for a $30\%$ contribution of hadronic resonance formation.

Figure 2

(Color online) $P_T$ dependence of $v_2$ for the pentaquark ${\Theta }^{+}$ (top) and the deuteron $d$. Thick solid line: fragmentation and recombination of a 5 (6) quark state for ${\Theta }^{+}$ $\left(d\right)$; thick dashed line: fragmentation and recombination of $K+N\left(p+n\right)$ for ${\Theta }^{+}$ $\left(d\right)$ as true for a molecular state; thin solid line: direct fragmentation (universal curve); thin dashed line: recombination of $K+N\left(p+n\right)$ only.