4π Physics with the plastic ball

Methods for analyzing anisotropic flow in relativistic nuclear collisions

“…The resolution correction used in earlier times at the Bevalac [28] is close to the present curve for values of χ 1 = v 1 √ 2N greater than about 1.5, which was generally true at the Bevalac. However, using the old procedure at the higher beam energies of the AGS or SPS would greatly overestimate the resolution and make the flow values too small.…”

“…Thus we discuss only anisotropic transverse flow from the particle azimuthal distributions at fixed rapidity or pseudorapidity. It appears very convenient to describe the azimuthal distributions by means of a Fourier expansion [28,25,24], and below we characterize different kinds of anisotropies as corresponding to different harmonics (in analogy/contrast to the description at low energies, where the three-dimensional event shape is characterized using multipole terminology). Anisotropic flow corresponding to the first two harmonics plays a very important role and we use special terms for them: directed and elliptic flow, respectively.…”