thesis or dissertation chair
- Coman, Luminita
A high resolution study of the quasielastic 2H(e, e′p)n reaction was performed in Hall A at the Thomas Jefferson Accelerator Facility in Newport News, Virginia. The measurements were performed at a central momentum transfer of |q| ~ 2400 MeV/c, and at a central energy transfer of ω ~ 1500 MeV, a four momentum transfer Q2 = 3.5 (GeV/c)2 , covering missing momenta from 0 to 0.5 GeV/c. The majority of the measurements were performed at Φ = 180° and a small set of measurements were done at Φ = 0°. The Hall A High Resolution Spectrometers (HRS) were used to detect coincident electrons and protons, respectively. Absolute 2H(e, e′p)n cross sections were obtained as a function of the recoiling neutron scattering angle with respect to q.
The experimental results were compared to a Plane Wave Impulse Approximation (PWIA) model and to a calculation that includes Final State Interaction (FSI) effects. Experimental 2H(e, e′p)n cross sections were determined with an estimated systematic uncertainty of 7 %. The general features of the measured cross sections are reproduced by Glauber based calculations that take the motion of the bound nucleons into account (GEA). Final State Interactions (FSI) contributions were found to depend strongly on the angle of the recoiling neutron with respect to the momentum transfer and on the missing momentum. We found a systematic deviation of the theoretical prediction of about 30 %. At small θnq (θnq < 60°) the theory overpredicts the cross section while at large θnq (θnq < 80°)the theory underestimates the cross sections.
We observed an enhancement of the cross section, due to FSI, of about 240 %, as compared to PWIA, for a missing momentum of 0.4 GeV/c at an angle of 75°. For missing momentum of 0.5 GeV/c the enhancement of the cross section due to the same FSI effects, was about 270 %. This is in agreement with GEA. Standard Glauber calculations predict this large contribution to occur at an angle of 90°. Our results show that GEA better describes the 2H(e, e′p)n reaction.
- July 12, 2007