  The Large Hadron Collider (LHC) experiments have revealed that the
predictions of the color glass condensate (CGC) tend to underestimate the
multiplicity at mid-rapidity. We develop and estimate a full second-order
viscous hydrodynamic model for the longitudinal expansion to find that the CGC
rapidity distributions are visibly deformed during the hydrodynamic stage due
to the interplay between the entropy production and the entropy flux to forward
rapidity. The results indicate the importance of viscous hydrodynamic evolution
with non-boost invariant flow for understanding the CGC in terms of the heavy
ion collisions.
