Investigation of particle coherence in Pb+Pb collisions at LHC

Abstract

Abstract. The observed particle distributions in Pb+Pb collisions at LHC are investigated. Monte Carlo simulations of the azimuthal anisotropy i.e. flow, and transverse momentum spectra provide insights in e.g. hadron genesis and in medio scattering. Simulations are made using the HYDJET++ model, which is based on parameterization of soft processes and generation of hard physics. The second and third event planes are implemented at this stage, thus generating the second and third order flows which are believed to provide the main part of the observed azimuthal distribution. Here, the ellipticity driven elliptic, and fluctuation driven triangular flow are used as differentiated observables. The elliptic and triangular flow are simulated in agreement with experimental data for pT < 3.5 GeV and centralities 0 − 50%. In connection to the simulation of azimuthal anisotropy, the particle transverse momentum spectra are simulated with accuracy, which provides a high degree of reproduction of geometric features. In extension to these simulations, the dependences on fragmentation processes are investigated through the second and third order flows, which are displaying sensitivity to particle coherence. In the simulations, particle coherence is thus seen to manifest itself through the azimuthal anisotropy.

Ultra-relativistic heavy-ion collisions - a hot cocktail of hydrodynamics, resonances and jets

“…Study of the fulfillment of Eq. (7) in the model and the role of jets in the increase of the ratio v 4 /v 2 2 and rise of its high-p T tail can be found in [26,30,31]. Pentagonal v 5 and hexagonal v 6 flow coefficients in non-central lead-lead collisions at √ s = 2.76 TeV are shown as functions of p T in Figs.…”

“…Again, jets increase the ratio of about 10% and cause the rise of the high-p T tail at p T ≥ 3 GeV/c. Other details concerning the peculiarities of the hexagonal flow development in HYDJET++ can be found in [16,17,31,34]. …”