Dissipative spin dynamics in relativistic matter

Using classical description of spin degrees freedom, we extend recent formulation the perfect-fluid hydrodynamics for spin-polarized fluids to case including dissipation. Our work is based on analysis kinetic equations massive particles with spin-1/2, collision terms treated in relaxation time approximation. The kinetic-theory framework determines structure viscous and diffusive allows explicitly calculate a complete set new coefficients that characterize dissipative dynamics.