# Neutral Pion Production in Au+Au Collisions at $\sqrt{s_{NN}}$ = 200 GeV

Abstract : The results of mid-rapidity ($0 < y < 0.8$) neutral pion spectra over an extended transverse momentum range ($1 < p_T < 12$ GeV/$c$) in $\sqrt{s_{NN}}$ = 200 GeV Au+Au collisions, measured by the STAR experiment, are presented. The neutral pions are reconstructed from photons measured either by the STAR Barrel Electro-Magnetic Calorimeter (BEMC) or by the Time Projection Chamber (TPC) via tracking of conversion electron-positron pairs. Our measurements are compared to previously published $\pi^{\pm}$ and $\pi^0$ results. The nuclear modification factors $R_{\mathrm{CP}}$ and $R_{\mathrm{AA}}$ of $\pi^0$ are also presented as a function of $p_T$ . In the most central Au+Au collisions, the binary collision scaled $\pi^0$ yield at high $p_T$ is suppressed by a factor of about 5 compared to the expectation from the yield of p+p collisions. Such a large suppression is in agreement with previous observations for light quark mesons and is consistent with the scenario that partons suffer considerable energy loss in the dense medium formed in central nucleus-nucleus collisions at RHIC.
Document type :
Journal articles

http://hal.in2p3.fr/in2p3-00409945
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Submitted on : Friday, August 14, 2009 - 2:50:32 PM
Last modification on : Friday, October 8, 2021 - 10:46:05 AM

### Citation

B.I. Abelev, M. M. Aggarwal, Z. Ahammed, A. V. Alakhverdyants, B. D. Anderson, et al.. Neutral Pion Production in Au+Au Collisions at $\sqrt{s_{NN}}$ = 200 GeV. Physical Review C, American Physical Society, 2009, 80, pp.044905-9. ⟨10.1103/PhysRevC.80.044905⟩. ⟨in2p3-00409945⟩

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