Diffraction and unitarity

I begin with a tribute to V.N. Gribov and then come to a particular problem which would be of interest for him. His first paper on reggeology was devoted to elastic scatterings of hadrons. Here, using the unitarity relation in combination with experimental data about the elastic scattering in the diffraction cone, I show how the shape and the darkness of the interaction region of colliding protons change with the increase of their energies. In particular, the collisions become fully absorptive at small impact parameters at LHC energies that results in some special features of inelastic processes as well. The possible evolution with increasing energy of the shape from the dark core at the LHC to the fully transparent one at higher energies is discussed. It implies that the terminology of the black disk would be replaced by the black torus.

Generalized Continuity Equation for Quasi-Hermitian Hamiltonians

The continuity relation is generalized to quasi-Hermitian one-dimensional Hamiltonians. As an application we show that the reflection and transmission coefficients computed with the generalized current obey the conventional unitarity relation for the continuous double delta function potential.

UNITARITY OF THE AHARONOV–BOHM SCATTERING AMPLITUDES

We discuss the unitarity relation of the Aharonov–Bohm scattering amplitude with the hope that it distinguishes between the differing treatment which employ different incident waves. We find that the original Aharonov–Bohm scattering amplitude satisfies the unitarity relation under the regularization prescription whose theoretical foundation does not appear to be understood. On the other land, the amplitude obtained by Ruijsenaars who uses plane wave as incident wave also satisfies the unitarity relation but in an unusual way.