Explicit model realizing parton-hadron duality

This project is in progress now. The basic ideas and preliminary results have been published in Refs. [11,15,19 (see CV)] and presented at series of the International Conferences [p1,p4-p8,p10,p13,p15-p18 (see CV)].

The basic idea in our approach is to use the off-mass-shell (i.e. Q^2-dependent) continuation of the dual amplitude with nonlinear complex Regge trajectories and then to relate its imaginary part to the proton structure function (via the total cross section) - for both its diffractive (background) and resonance components. Ideally, one could think about dual amplitude as a complex function of s, t and Q^2 (e.g. the deeply virtual Compton scattering amplitude), which satisfies the general requirements of the theory, and which is reducible to a hadronic amplitude or a structure function of deep inelastic scattering in relevant kinematic limits. The Regge trajectories play a crucial role in the dynamics of the strong interactions. Actually, in the dual models the trajectories can be considered as the basic dynamical variables, replacing the usual Mandelstam variables s, t and u. Their form, for example, determines completely the spectrum of resonances in ep scattering [19,p13,p15-p18 (see CV)]. The parameters of the trajectories can be fitted independently of the masses and widths of the known resonances, therefore, in principle, they reflect more adequately the position of the peaks in $ep$ scattering, formed by the interplay of different resonances.

In our modeling the low energy background is modeled by a dual model contribution from direct-channel exotic trajectory, dual to the exchanged Pomeron. While at high energies it matches the Regge pole behavior, dominated by a pomeron exchange, at low energies it produces a smooth, structureless behavior of the total cross section. The exact calculations of DAMA integral are presented in Ref. [p18 (see CV)].

In Refs. [15,p5-p8,p10 (see CV)] we obtained the qualitative agreement with experimental data, based on Dual Model with Mandelstam Analyticity (DAMA) and introducing Q^2-dependence through the DAMA parameter g.

In Refs. [19,p4,p13,p15-p17 (see CV)] we use a simplified phenomenological model, motivated by a termination of the real part of nonlinear complex Regge trajectories, to make a quantitative fit to SLAC and JLab data.