Date of Award

Summer 2014

Document Type


Degree Name

Doctor of Philosophy (PhD)



Committee Director

S. E. Kuhn

Committee Member

A. Radyushkin

Committee Member

S. Bueltmann

Committee Member

A. Godunov

Committee Member

N. Diawara


The EG1-DVCS experiment with CLAS at Jefferson Lab collected semi-inclusive pion electro-production data on longitudinally polarized solid state NH3 and ND3 targets with longitudinally polarized electrons of approximately 6 GeV energy. Data on all three pion channels, π +, π– and π0, were collected simultaneously. The charged pions were identified by their time-of-flight information whereas the neutral pions were reconstructed from the invariant mass of two photons. The experiment covered a wide kinematic range: 1 GeV 2Q2 ≤ 3.2 GeV2, 0.12 ≤ xB ≤ 0.48, 0.0 GeV ≤ Ph ≤ 1.0 GeV and 0.3 ≤ z ≤ 0.7. The beam single (ALU), target single (AUL) and beam-target double ( ALL) spin azimuthal asymmetries in semi-inclusive deep-inelastic scattering (SIDIS) off the proton and the deuteron extracted from the data are presented. The results of the azimuthal asymmetries for the proton are presented as a function of two variables: (xB, Ph), (z, P h) and (xB, z). Due to limited statistics, the azimuthal asymmetries for the deuteron are presented as a function of a single variable for the variables xB, z and Ph. Some theoretical and phenomenological predictions as well as earlier published results are compared with the results from this analysis. All the results are plotted and suitably tabulated for further analysis.

The SIDIS azimuthal asymmetries are convolutions of fragmentation functions and transverse momentum dependent parton distribution functions (TMDs). The TMDs describe transverse momenta and spins of quarks and gluons inside nucleons. They open a window on the contribution of the orbital angular momentum of the quarks and gluons to the total spin of the nucleons. The results presented in this work are sensitive to these leading twist TMDs: f 1, g1, h⊥ 1L, and h⊥ 1. The significant precision of the results from this analysis will highly constrain the extractions of the associated TMDs which will substantially contribute towards further investigation into the partonic structure of nucleon intrinsic angular momentum.


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