Elliptic Flow at Large Transverse Momenta from Quark Coalescence
Abstract
We show that hadronization via quark coalescence enhances hadron elliptic flow at large ${p}_{\ensuremath{\perp}}$ relative to that of partons at the same transverse momentum. Therefore, compared to earlier results based on covariant parton transport theory, more moderate initial parton densities $dN/d\ensuremath{\eta}(b=0)\ensuremath{\sim}1500--3000$ can explain the differential elliptic flow ${v}_{2}({p}_{\ensuremath{\perp}})$ data for $\mathrm{A}\mathrm{u}+\mathrm{A}\mathrm{u}$ reactions at $\sqrt{s}=130$ and $200A\text{ }\mathrm{G}\mathrm{e}\mathrm{V}$ from BNL RHIC. In addition, ${v}_{2}({p}_{\ensuremath{\perp}})$ could saturate at about 50% higher values for baryons than for mesons. If strange quarks have weaker flow than light quarks, hadron ${v}_{2}$ at high ${p}_{\ensuremath{\perp}}$ decreases with relative strangeness content.