6 research outputs found
Explicit Model Realizing Parton-Hadron Duality
We present a model that realizes both resonance-Regge (Veneziano) and
parton-hadron (Bloom-Gilman) duality. We first review the features of the
Veneziano model and we discuss how parton-hadron duality appears in the
Bloom-Gilman model. Then we review limitations of the Veneziano model, namely
that the zero-width resonances in the Veneziano model violate unitarity and
Mandelstam analyticity. We discuss how such problems are alleviated in models
that construct dual amplitudes with Mandelstam analyticity (so-called DAMA
models). We then introduce a modified DAMA model, and we discuss its
properties. We present a pedagogical model for dual amplitudes and we construct
the nucleon structure function F2(x,Q2). We explicitly show that the resulting
structure function realizes both Veneziano and Bloom-Gilman duality.Comment: 11 pages, 8 figure
Off mass shell dual amplitude with Mandelstam analyticity
A model for the -dependent dual amplitude with Mandelstam analyticity
(DAMA) is proposed. The modified DAMA (M-DAMA) preserves all the attractive
properties of DAMA, such as its pole structure and Regge asymptotics, and leads
to a generalized dual amplitude . This generalized amplitude can be
checked in the known kinematical limits, i.e. it should reduce to the ordinary
dual amplitude on mass shell, and to the nuclear structure function when .
In such a way we complete a unified "two-dimensionally dual" picture of strong
interaction. By comparing the structure function , resulting from M-DAMA,
with phenomenological parameterizations, we fix the -dependence in M-DAMA.
In all studied regions, i.e. in the large and low limits as well as in the
resonance region, the results of M-DAMA are in qualitative agreement with the
experiment.Comment: 20 pages, 3 figures; to appear in Phys.Atom.Nuc