Quark–hadron duality in neutrino interactions
This project focused on the question of whether Bloom–Gilman quark–hadron duality, originally observed in electron scattering, also appears in neutrino interactions and can be used to build practical models of nucleon structure functions for neutrino cross-section calculations. The broader motivation was to understand how descriptions based on baryon resonances can be matched to partonic structure functions, thereby improving modeling in the transition region between resonance production and deep-inelastic scattering.
The first part of the project analyzed the Rein–Sehgal model in the context of duality. The resonance-region structure functions were integrated in the Nachtmann variable and compared with deep-inelastic expectations. This study showed that, if the resonance region is taken as roughly W between threshold and 2 GeV, duality is seen for neutrino–proton scattering in the F2 structure function over a moderate range of momentum transfer, but it is much weaker or absent for neutron and isoscalar targets. The results therefore demonstrated that duality in neutrino reactions is more selective than in the electromagnetic case.
A related analysis examined how reliably the Rein–Sehgal model can be used to reconstruct the inclusive cross section in the resonance region. Because the argument depends on how single-pion channels are related to the full inelastic response, several procedures for estimating these contributions were compared. This allowed us to identify the kinematic conditions under which resonance-based models can meaningfully reproduce averaged deep-inelastic behavior and where such an approach breaks down.
The project was then extended to a broader discussion of quark–hadron duality in lepton scattering, including its usefulness for modeling inclusive structure functions in the resonance region. These studies showed that duality can become a practical phenomenological tool, but only within clearly defined kinematic and target-dependent limits.
Funding: [place for funding information]
References:
Nucl. Phys. A 781, 227–246 (2007)
Nucl. Phys. B (Proc. Suppl.) 159, 241–242 (2006)
Acta Phys. Polon. B 37, 2321–2328 (2006)
AIP Conf. Proc. 1222, 238–242 (2010)
Collaborators: Jan Sobczyk and Cezary Juszczak
Figure: [place for illustration]