Azimuth quadrupole component spectra on transverse rapidity ${\mathbf{y}}_{\mathbf{t}}$ for identified hadrons from Au-Au collisions at $\sqrt{s_{NN}}=$ 200 GeV

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 lambdas/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 $\Delta y_{t0}\sim 0.6$. The quadrupole spectra have a Lévy form similar to the soft component of the single-particle spectrum, but with significantly reduced ($\sim 0.7\times$) 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 $p_t^{\prime }$ ($p_t$ in the boost frame) times the ratio of quadrupole spectrum to single-particle spectrum. That ratio in turn implies that above 0.5 GeV/c the form of $v_2(p_t)$ is dominated by the hard component of the single-particle spectrum (interpreted as due to minijets). It is therefore unlikely that so-called {\em constituent-quark scaling} attributed to $v_2$ is relevant to soft hadron production mechanisms (e.g., chemical freezeout).

22 pages, 17 figures

References in corpus (5)

• Viscosity Information from Relativistic Nuclear Collisions: How Perfect is the Fluid Observed at RHIC?
• Centrality dependence of charged hadron and strange hadron elliptic flow from sqrt(s_NN) = 200 GeV Au+Au collisions
• Centrality evolution of $p_t$ and $y_t$ spectra from Au-Au collisions at $\sqrt{s_{NN}}=200$ GeV
• The RHIC azimuth quadrupole: "perfect liquid" or gluonic radiation?
• The azimuth structure of nuclear collisions -- I