On limitation of mass spectrum in non-Hermitian cal PT-symmetric models with the γ₅-dependent mass term

The modified Dirac equations for the massive particles with the replacement of the physical mass m with the help of the relation m→ m₁ + γ₅ m₂ are investigated. It is shown that for a free fermion theory with a γ₅ mass term, the finiteness of the mass spectrum at the value m_max= {m₁}²/2m₂ takes place. In this case the region of the unbroken cal PT-symmetry may be expressed by means of the simple restriction of the physical mass mleq m_max. Furthermore, we have that the areas of unbroken cal PT-symmetry m_1geq m_2geq 0, which guarantees the reality values of the physical mass m, consists of three different parametric subregions: i) 0leq m₂ < m₁/sqrt{2}, \,\,ii) m₂=m₁/sqrt{2}=m_max, \,\,(iii)m₁/sqrt{2}< m₂ leq m₁. It is vary important, that only the first subregion (i) defined mass values m₁,m₂, which correspond to the description of traditional particles in the modified models, because this area contain the possibility transform the modified model to the ordinary Dirac theory. The second condition (ii) is defined the "maximon" - the particle with maximal mass m=m_max. In the case (iii) we have to do with the unusual or "exotic" particles for description of which Hamiltonians and equations of motion have no a Hermitian limit. The formulated criterions may be used as a major test in the process of the division of considered models into ordinary and "exotic fermion theories".