76 research outputs found
Generalized baryon form factors and proton structure functions in the Sakai-Sugimoto model
We investigate the production of positive parity baryon resonances in proton
electromagnetic scattering within the Sakai-Sugimoto model. The latter is a
string model for the non-perturbative regime of large QCD. Using
holographic techniques we calculate the generalized Dirac and Pauli form
factors that describe resonance production. We use these results to estimate
the contribution of resonance production to the proton structure functions.
Interestingly, we find an approximate Callan-Gross relation for the structure
functions in a regime of intermediate values of the Bjorken variable.Comment: v3: 38 pages, 25 figures. We added a new subsection in order to
compare our results with experimental data. To appear in Nucl. Phys.
Production of negative parity baryons in the holographic Sakai-Sugimoto model
We extend our investigation of resonance production in the Sakai-Sugimoto
model to the case of negative parity baryon resonances. Using holographic
techniques we extract the generalized Dirac and Pauli baryon form factors as
well as the helicity amplitudes for these baryonic states. Identifying the
first negative parity resonance with the experimentally observed S_{11}(1535),
we find reasonable agreement with experimental data from the JLab-CLAS
collaboration. We also estimate the contribution of negative parity baryons to
the proton structure functions.Comment: 1+30 pages, 8 figures. v3: typos corrected, references added, section
2 and 3 shortened, improved discussion of helicity amplitudes and comparison
with experimental result
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