Non-conformal attractor in boost-invariant plasmas

We study the dissipative evolution of (0+1)-dimensionally expanding media with Bjorken symmetry using Boltzmann equation for massive particles in relaxation-time approximation. Breaking conformal by a mass induces non-zero bulk viscous pressure medium. It is shown that even small (in units local temperature) drastically modifies well-known attractor shear Reynolds number previously observed massless systems. For generic nonzero particle mass, neither nor relax quickly to non-equilibrium attractor; they approach hydrodynamic limit only late, at values inverse numbers. Only longitudinal pressure, which combination thermal, and pressures, continues show early far-off-equilibrium attractor, driven rapid expansion times. Second-order hydrodynamics based on gradient around locally isotropic thermal equilibrium fails reproduce this attractor.