Azimuth Quadrupole Systematics in Au-Au Collisions

Abstract

We have measured $p_t$-dependent two-particle number correlations on azimuth and pseudorapidity for eleven centralities of $\sqrt{s_{NN}}=62$ and 200~GeV Au-Au collisions at STAR. 2D fits to these angular correlations isolate the azimuth quadrupole amplitude, denoted $2v_2^2\{2D\}(p_t)$, from localized same-side correlations. Event-plane $v_2(p_t)$ measurements within the STAR TPC acceptance can be expressed as a sum of the azimuth quadrupole and the quadrupole component of the same-side peak. $v_2\{2D\}(p_t)$ can be transformed to reveal quadrupole $p_t$ spectra which are approximately described by a fixed transverse boost and universal Lévy form nearly independent of centrality. A parametrization of $v_2\{2D\}(p_t)$ can be factored into centrality and $p_t$-dependent pieces with a simple $p_t$ dependence above 0.75 GeV/c. Results from STAR are compared to published data and model predictions.

Conference proceedings for Hot Quarks 2010

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