Quark-Hadron Duality

Quark-hadron duality and its potential applications are discussed. We focus on theoretical efforts to model duality.Comment: Plenary Talk given at Baryons 2002, Newport News, VA, March 200

Factorization Breaking of AdTA^T_d for polarized deuteron targets in a relativistic framework

We discuss the possible factorization of the tensor asymmetry $A^T_d$ measured for polarized deuteron targets within a relativistic framework. We define a reduced asymmetry and find that factorization holds only in plane wave impulse approximation and if p-waves are neglected. Our numerical results show a strong factorization breaking once final state interactions are included. We also compare the d-wave content of the wave functions with the size of the factored, reduced asymmetry and find that there is no systematic relationship of this quantity to the d-wave probability of the various wave functions

Factorization Breaking of AdT for Polarized Deuteron Targets in a Relativistic Framework

We discuss the possible factorization of the tensor asymmetry AdT measured for polarized deuteron targets within a relativistic framework. We define a reduced asymmetry and find that factorization holds only in plane wave impulse approximation and if p waves are neglected. Our numerical results show a strong factorization breaking once final state interactions are included. We also compare the d-wave content of the wave functions with the size of the factored, reduced asymmetry and find that there is no systematic relationship of this quantity to the d-wave probability of the various wave functions

Momentum Distributions for \u3csup\u3e2\u3c/sup\u3eH (\u3ci\u3ee, e\u27 p\u3c/i\u3e)

Background: A primary goal of deuteron electrodisintegration is the possibility of extracting the deuteron momentum distribution. This extraction is inherently fraught with difficulty, as the momentum distribution is not an observable and the extraction relies on theoretical models dependent on other models as input. Purpose: We present a new method for extracting the momentum distribution which takes into account a wide variety of model inputs thus providing a theoretical uncertainty due to the various model constituents. To test the extraction, pseudodata were generated, and the extracted “experimental” distribution, which has theoretical uncertainty accounted by this extraction method, can be compared to the theoretical distribution. This procedure can provide an upper bound on the deuteron momentum distribution. Method: The calculations presented here are using a Bethe-Salpeter-like formalism with a wide variety of bound state wave functions, form factors, and final state interactions. Results: In the examples we compared, the original distribution was typically within the error band of the extracted distribution. The input wave functions do contain some outliers which are discussed in the text. Due to the reliance on the theoretical calculation to obtain this quantity, any extraction method should account for the theoretical error inherent in these calculations due to model inputs. Conclusions: The extraction method works well and provides a systematic way to investigate the deuteron momentum distribution, while accounting for theoretical uncertainty and providing a theoretical error band

Target Polarization for 2H⃗(e,e′p)n^2 \vec H(e,e'p)n at GeV energies

We perform a fully relativistic calculation of the $^2 \vec H(e,e'p)n$ reaction in the impulse approximation employing the Gross equation to describe the deuteron ground state, and we use the SAID parametrization of the full NN scattering amplitude to describe the final state interactions (FSIs). The formalism for treating target polarization with arbitrary polarization axes is discussed, and general properties of some asymmetries are derived from it. We show results for momentum distributions and angular distributions of various asymmetries that can only be accessed with polarized targets.Comment: 30 pages, 9 figure

Modeling quark-hadron duality in polarization observables

We apply a model for the study of quark-hadron duality in inclusive electron scattering to the calculation of spin observables. The model is based on solving the Dirac equation numerically for a scalar confining linear potential and a vector color Coulomb potential. We qualitatively reproduce the features of quark-hadron duality for all potentials considered, and discuss the onset of scaling and duality for the responses, spin structure functions, and polarization asymmetries. Duality may be applied to gain access to kinematic regions which are hard to access in deep inelastic scattering, namely for $x_{Bj} \to 1$, and we discuss which observables are most suitable for this application of duality