Suppression of ${\pi }^0$ production at large $p_{\perp }$ in central $Au+Au$ collisions at $\sqrt{s_{NN}}=200$ GeV and quark-gluon plasma

Abstract

We investigate the suppression of ${\pi }^0$-spectrum in a wide range of $p_{\perp }$ up 60 GeV/c which is caused by the energy loss of the gluon and quark jets in quark-gluon plasma. The physical characteristics of initial and mixed phases were found in the effective quasiparticle model by analogy with previous work \cite{5}. The PHENIX data up 10 GeV/c within the limits of precision are described by quasiparticle model with decrease of the thermal gluon mass and effective coupling in the region of phase transitin (at $T\to T_c$ from above). We also take into account the intrinsic transverse momentum $k_{\perp }$ of partons. The suppression factor $R_{AA}(p_{\perp })$ shows the weak rise with increase of $p_{\perp }$ above 4 GeV/c, then it reaches smooth maximum at $p_{\perp }\sim 20$ GeV/c and then decrease at $p_{\perp }\sim 60$ GeV/c again to value $R_{AA}$ at $p_{\perp }\simeq$ 4 GeV/c. The factor $R_{AA}$ in this range of $p_{\perp }$ is changihg weakly if intrinsic momentum $k_{\perp }$ is taken into account.

Comments: 14 pages, 4 figures