Inhaltszusammenfassung

The directed flow of charged particles at mid-rapidity is measured in Pb-Pb collisions at sqrt{s_NN}=2.76 TeV relative to the collision plane defined by the spectator nucleons. Both, the rapidity odd (v_1^odd) and even (v_1^even) directed flow components are reported. The v_1^odd component has a negative slope as a function of pseudorapidity similar to that observed at the highest RHIC energy, but with about a three times smaller magnitude. The v^even component is found to be non-zero and ind...The directed flow of charged particles at mid-rapidity is measured in Pb-Pb collisions at sqrt{s_NN}=2.76 TeV relative to the collision plane defined by the spectator nucleons. Both, the rapidity odd (v_1^odd) and even (v_1^even) directed flow components are reported. The v_1^odd component has a negative slope as a function of pseudorapidity similar to that observed at the highest RHIC energy, but with about a three times smaller magnitude. The v^even component is found to be non-zero and independent of pseudorapidity. Both components show little dependence on the collision centrality and change sign at transverse momenta around 1.2-1.7 GeV/c for midcentral collisions. The shape of v_1^even as a function of transverse momentum and a vanishing transverse momentum shift along the spectator deflection for v_1^even are consistent with dipole-like initial density fluctuations in the overlap zone of the nuclei. » weiterlesen» einklappen

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DDC Sachgruppe:
Physik