1. Viscous Hydrodynamic Evolution for the CGC at RHIC and LHC Akihiko Monnai Department of Physics, The University of Tokyo Collaborator: Tetsufumi Hirano The 17 th Heavy Ion Café March 3 rd 2011, The University of Tokyo

2. Multiplicity at LHC CGC predictions vs. LHC data ALICE data (most central 0-5%) Is the CGC not applicable at LHC? CGC Pb+Pb, 2.76 TeV at η = 0 K. Aamodt et al. PRL105 252301 Color glass condensate (CGC): Description of saturated gluons in nuclei before a collision The 17 th Heavy Ion Café – Open Discussion Akihiko Monnai

3. Multiplicity at LHC CGC parameters CGC for heavy ion collisions Saturation scale in MC-KLN model Fixed via direct comparison with data Initial condition From the CGC Hydrodynamic evolution Observed particle distribution dN/dy λ=0.28 λ=0.18 λ=0.38 (RHIC data compatible with λ~0.28) Is the hydrodynamic effect important ? a missing piece! Initial condition From the CGC Observed particle distribution The 17 th Heavy Ion Café – Open Discussion Akihiko Monnai H. J. Drescher and Y. Nara, PRC 75, 034905 PRC 76, 041903

4. Multiplicity at LHC Effects of (1+1)D Viscous Hydro If the true λ is larger at RHIC, it enhances dN/dy for LHC; A possible candidate for explaining the “gap” at LHC? Outward entropy fluxFlattening Entropy productionEnhancement RHIC LHC AM and T. Hirano, arXiv:1102.5053 [nucl-th] The 17 th Heavy Ion Café – Open Discussion Akihiko Monnai