Elliptic flow from colour strings

Abstract

It is shown that the elliptic flow can be successfully described in the colour string picture with fusion and percolation provided anistropy of particle emission from the fused string is taken into account. Two possible sources of this anisotropy are considered, propagation of the string in the transverse plane and quenching of produced particles in the strong colour field of the string. Calculations show that the second source gives an overwhelming contribution to the flow at accessible energies.

Transport coefficient to trace anomaly in the clustering of color sources approach

“…In the Color String Percolation Model (CSPM) the relevant parameter is the transverse string density ξ = N s S 1 /S n where N s is the number of strings, S 1 the transverse area of a single string, S 1 = πr 2 0 and S n the overlap area of the collision, which depends on the impact parameter [15,16]. The following expression was obtained for η/s [14].…”

Rapidity dependence of particle densities inppandAAcollisions

“…In the impact parameter plane due to the confinement, the color of strings is confined to a small area in transverse space S 1 = πr 2 0 with r 0 ∼ 0.2−0.3 fm, these strings decay into new ones by qq −qq pair production and subsequently hadronize to produce the observed hadrons. In the impact parameter plane the strings appear as discs and as energy-density increases the discs overlap, fuse, and percolate, leading to the reduction of the overall color [8][9][10]. A cluster of n strings behaves as a single string with energy momentum corresponding to the sum of the individual ones.…”

Nonlinearity of the forward-backward correlation function in the model with string fusion

“…This discrete version of string fusion model [5,6] was introduced in [17] and then was exploited for a description of various phenomena (correlations, anisotropic azimuthal flows, the ridge) in high energy hadronic collisions [8][9][10][11][12][19][20][21]. In this approach one splits the impact parameter plane into M cells with the area equal to the transverse area of single string, σ str , and supposes the fusion of all strings with the centers in a given cell.…”