Energy dependent growth of the nucleon and hydrodynamic initial conditions

Abstract

Due to gluon saturation, the growth of the inelastic nucleon-nucleon cross section with increasing collision energy sqrt(s) results in a broadening of the nucleon's density distribution in position space. This leads to a natural smoothing of the initial energy density distribution in the transverse plane of the matter created near midrapidity in heavy-ion collisions. We study this effect for fluctuating initial conditions generated with the Monte Carlo Kharzeev-Levin-Nardi (MC-KLN) model for Au+Au collisions at the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC). We argue that at the LHC viscous hydrodynamics is applicable at earlier times than at RHIC, not only because of the higher temperature but also since the length scale over which the initial pressure fluctuates increases with collision energy.

8 pages, 4 figures. Minor edits relative to v1 (2 references, 1 footnote). This version accepted by Physical Review C. Note that Fig.3 posted here is a higher-resolution version than used by the journal

References in corpus (8)

• Glauber Modeling in High Energy Nuclear Collisions
• Triangular flow in hydrodynamics and transport theory
• Translation of collision geometry fluctuations into momentum anisotropies in relativistic heavy-ion collisions
• Effects of fluctuations on the initial eccentricity from the Color Glass Condensate in heavy ion collisions
• Eccentricity fluctuations from the Color Glass Condensate at RHIC and LHC
• Proton-proton elastic scattering at the LHC energy of {\surd} = 7 TeV
• Eccentricity fluctuation effects on elliptic flow in relativistic heavy ion collisions
• N=4 SYM and QCD motivated approach to soft interactions at high energies

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