Radiative jet energy loss in a three-dimensional hydrodynamical medium and highpTazimuthal asymmetry ofπ0suppression at mid and forward rapidity in

Abstract

Radiative jet energy loss in a three-dimensional hydrodynamical medium and high p T azimuthal asymmetry of π 0 suppression at mid and forward rapidity at RHIC The nuclear modification factor RAA for π0 production in Au+Au collisions at √ s = 200 AGeV is calculated, and studied at high transverse momenta pT . The soft thermalized nuclear medium is described within the framework of relativistic ideal three-dimensional hydrodynamics. The energy loss of partonic jets is evaluated in the context of gluon bremsstrahlung in the thermalized partonic matter. We provide a systematic analysis of the azimuthal asymmetry of π0 suppression at high pT in central and non-central collisions, at mid and forward rapidity. The determination of RAA as a function of pT , at different azimuthal angles, and different rapidities makes for a stringent test of our theoretical understanding of jet energy loss over a variety of in-medium path lengths, temperatures and initial partonic jet energies. This lays the groundwork for a tomography of the nuclear medium.

Radiative and Collisional Jet Energy Loss in the Quark-Gluon Plasma at the BNL Relativistic Heavy Ion Collider

“…Until recently most jet quenching calculations used simple medium models only loosely constrained by the value of bulk observables. Previously we presented a calculation of R AA in central and non-central collisions using the AMY formalism and a (3+1) dimensional hydrodynamical model constrained by soft observables at RHIC [12]. Here we incorporate collisional energy loss into this framework.…”

“…The ω < 0 part of the integration incorporates processes which increase a particle's energy. The radiative part of the transition rate is discussed in [12,19,20]. Now we must add the contribution from collisional energy loss.…”

“…Bremsstrahlung energy loss has been calculated in several theoretical formalisms before [4,5,6,7,8,9]. Recently such bremsstrahlung calculations were implemented in models employing relativistic ideal (3+1)-dimensional hydrodynamics in order to calculate the nuclear modification factor R AA of neutral pions at RHIC [10,11,12]. Early estimates of the collisional energy loss which used asymptotic arguments indicated that the radiative energy loss is much larger than elastic energy loss [13].…”

“…Brief review of the formalism -For details of the calculation of the initial distributions of hard partons in the early stage of the collision and the subsequent propagation through the hot and dense quark gluon plasma as well as the fragmentation we refer the reader to [12] and references therein. We concentrate here on the incorporation of collisional energy loss in the formalism.…”

“…The jet momentum distribution P (E, t) = dN (E,t) dE evolves in the medium according to a set of coupled Fokker-Planck type rate equations, which have the following generic form [12]:…”