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AM and T. Hirano, Phys. Lett. B 703, 583 (2011). V iscous Hydrodynamic Deformation in Rapidity Distributions of the Color Glass Condensate. Akihiko Monnai Department of Physics, The University of Tokyo Collaborator: Tetsufumi Hirano. Workshop for Particle Correlations and Femtoscopy 2011
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AM and T. Hirano, Phys. Lett. B 703, 583 (2011) Viscous Hydrodynamic Deformation in Rapidity Distributions of the Color Glass Condensate Akihiko Monnai Department of Physics, The University of Tokyo Collaborator: Tetsufumi Hirano • Workshop for Particle Correlations and Femtoscopy 2011 • September24th 2011, The University of Tokyo,Japan
Introduction • Quark-gluon plasma (QGP) at relativistic heavy ion collisions Hadron phase (crossover) QGPphase sQGP (wQGP?) • RHICexperiments (2000-) The QGP quantified as a nearly-perfect fluid Viscosityis important in detailed analyses • LHCexperiments (2010-) Heavy ion collisions of higher energies Will the RHIC modeling work at LHC? Introduction
Introduction • Modeling a high-energy heavy ion collision particles t t Freezeout Hadronic cascade Hydro to particles QGPphase Hydrodynamic stage hadronic phase Pre-equilibrium Initial condition z Color glass condensate Color glass condensate (CGC) Description of saturated gluons in the nuclei before a collision (τ < 0 fm/c) Relativistic hydrodynamics Description of collective motion of the QGP (τ ~ 1-10 fm/c) The First ALICE Result
The First ALICE Result • Mid-rapidity multiplicity K. Aamodtet al. PRL105252301 Pb+Pb, 2.76 TeV at η = 0 CGC Motivation ALICE data (most central 0-5%) The CGC is fit to RHIC data; What is happening at LHC? CGC in Heavy Ion Collisions
CGC in Heavy Ion Collisions • Saturation scale in MC-KLN model D. Kharzeevet al., NPA 730, 448 H. J. Drescher and Y. Nara, PRC 75, 034905; PRC 76, 041903 λ=0.38 Fixed via directcomparison with data λ=0.28 λ=0.18 : thicknessfunction : momentum fraction of incident particles dN/dy dNch/dη gets steeper with increasing λ; RHIC data suggest λ~0.28 Initial condition from the CGC Observed particle distribution Observed particle distribution Initial condition from the CGC Hydrodynamic evolution A missing piece! CGC in Heavy Ion Collisions
CGC in Heavy Ion Collisions • CGC + Hydrodynamic Model Observed particle distribution Initial condition from the CGC Hydrodynamic evolution A missing piece! In this work… We estimate hydrodynamic effects with (i) non-boost invariant expansion for the CGC (ii) viscous corrections The first time the CGC rapidity distribution is discussed in terms of viscous hydrodynamics Hydrodynamic Model
Hydrodynamic Model • Full 2nd order viscous hydrodynamicequations + Energy-momentum conservation AM and T. Hirano, NPA 847, 283 EoM for bulk pressure EoM for shear tensor All the terms are kept Solve in (1+1)-D relativistic coordinates (= no transverse flow) with Landau frame where local energy flux is the flow Model Input for Hydro
Model Input for Hydro • Equation of state and transport coefficients • Boundary conditionsat the initial time Equation of State: Lattice QCD S. Borsanyiet al., JHEP 1011, 077 P. Kovtunet al., PRL 94, 111601 Shear viscosity: η = s/4π A. Hosoyaet al., AP 154, 229 Bulk viscosity: ζeff = (5/2)[(1/3) – cs2]η AM and T. Hirano, NPA 847, 283 Relaxation times: Kinetic theory 2nd order coefficients: Kinetic theory Initial flow: Bjorken flow (i.e. flow rapidity Yf = ηs) Energy distribution: MC-KLN type CGC (averaged over transverse area) Dissipative currents: Results
Results • Distributions at isothermal hypersurfaceTf = 0.16 TeV LHC RHIC Outward entropy flux Flattening Entropy production Enhancement If the true λ is larger at RHIC, it enhances dN/dy at LHC; Hydro effect is a candidate for explaining the “gap” at LHC Results
Results • Hydrodynamic parameter dependences (at the LHC) • CGC parameter dependence to be explored • Entropy production is roughly proportional to viscous coefficients • Shear viscous effects are dominant in the QGP phase Fix the real λ from rapidity distribution and centrality dependences Summary and Outlook
Summary and Outlook • We solved full 2nd order viscous hydro in (1+1)-dimensions for the “shattered” color glass condensate • Future prospect includes: • Analyses on the CGC parameter dependences, rcBK, etc… • Estimation of the effects of transverse flow via developing (3+1)-dimensional viscous hydrodynamic model, etc… Non-trivial deformation of CGC rapidity distribution due to (i) outward entropy flux (non-boost invariant effect) (ii) entropy production (viscous effect) Viscous hydrodynamic effect may play an important role in understanding the seemingly large multiplicity at LHC AM & T. Hirano, in preparation The End
The End • Thank you for listening! • Website: http://tkynt2.phys.s.u-tokyo.ac.jp/~monnai/index.html