Azimuth quadrupole component spectra on transverse rapidityytfor identified hadrons from Au-Au collisions atsNN=200GeV

Abstract

I present the first isolation of azimuth quadrupole components from published ${v}_{2}({p}_{t})$ data (called elliptic flow) as spectra on transverse rapidity ${y}_{t}$ for identified pions, kaons, and \ensuremath{\Lambda}'s/protons from minimum-bias Au-Au collisions at 200 GeV. The form of the spectra on ${y}_{t}$ indicates that the three hadron species are emitted from a common boosted source with boost $\ensuremath{\Delta}{y}_{t0}~0.6$. The quadrupole spectra have a L\'evy form similar to the soft component of the single-particle spectrum, but with significantly reduced ($~0.7$ times) slope parameters $T$. Comparison of quadrupole spectra with single-particle spectra suggests that the quadrupole component comprises a small fraction (5%) of the total hadron yield, contradicting the hydrodynamic picture of a thermalized, flowing bulk medium. The form of ${v}_{2}({p}_{t})$ is, within a constant factor, the product of ${p}_{t}^{'}$ (${p}_{t}$ in the boost frame) times the ratio of quadrupole spectrum to single-particle spectrum. That ratio in turn implies that above $0.5 \mathrm{GeV}/c$, the form of ${v}_{2}({p}_{t})$ is dominated by the hard component of the single-particle spectrum (interpreted as being due to minijets). It is therefore unlikely that the so-called constituent-quark scaling attributed to ${v}_{2}$ is relevant to soft hadron production mechanisms (e.g., chemical freeze-out).