Relativistic dissipative hydrodynamic equations are extended by taking into
account particle number changing processes in a gluon system, which expands in
one dimension boost-invariantly. Chemical equilibration is treated by a rate
equation for the particle number density based on Boltzmann equation and Grad's
ansatz for the off-equilibrium particle phase space distribution. We find that
not only the particle production, but also the temperature and the momentum
spectra of the gluon system, obtained from the hydrodynamic calculations, are
sensitive to the rates of particle number changing processes. Comparisons of
the hydrodynamic calculations with the transport ones employing the parton
cascade BAMPS show the inaccuracy of the rate equation at large shear viscosity
to entropy density ratio. To improve the rate equation, the Grad's ansatz has
to be modified beyond the second moments in momentum.Comment: 20 pages, 11 figure
