Separation of elastic and inelastic processes in the relaxation time   approximation for collision integral
  We introduce a generalised relaxation-time-approximation form of the collision term in the Boltzmann kinetic equation that allows for using different relaxation times for elastic and inelastic collisions. The efficacy of the proposed framework is demonstrated with the numerical calculations that describe systems with different relations between the two relaxation times and the evolution time of the system. 
Wojciech Florkowski and Radoslaw Ryblewski
nucl-th hep-ph