Graviton reggeization and high energy gravitational scattering of scalar particles

In this paper we consider a high energy scattering of free scalar particles through a gravitational field. The amplitude of the scattering in this limit is governed by reggeized gravitons. Therefore, we discuss an appearance of the reggeized gravitons in the framework of Einstein-Hilbert gravity and consider Lipatov's effective action for the reggeized gravitons. We calculate the trajectory of the corresponding t-channel amplitude in the framework and thereafter define the leading order amplitude of scattering of two massive scalar particles. A difference of the amplitude obtained at high energy limit from the amplitude in Newton's (low energy) limit is discussed. It is demonstrated, that the graviton's propagator reggeization leads to the amplification of the high energy amplitude. Effectively, this enhancement of the amplitude appears as a redefinition of the masses of particles involved in the scattering. An impact factor of the interaction of scalar particle with the reggeized gravitons is also calculated and possible applications of the approach are discussed as well.