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Title Study of the N to Delta Transition via p(e,e'p)pi0 Reaction
Authors Zhengwei Chai
JLAB number JLAB-PHY-03-174
LANL number (None)
Other number DOE/ER/40150-2747
Document Type(s) (Thesis) 
Supported by U.S. Naval Research: No
Supported by Jefferson Lab LDRD Funding: No
A PHD thesis
Advisor(s) :
   William Bertozzi (MIT)
Publication Abstract: A precise measurement of the $p(\vec{e}, e^{\prime}\vec{p})\pi^0$ reaction at the $\Delta(1232)$ resonance with $Q^2$=0.9,1.1$(GeV/c)^2$ was conducted in experimental Hall A at the Jefferson Lab. The angular distributions of the coincidence cross section and recoil polarization in the pion electro-production process were used for the extraction of both the unpolarized and polarized response functions. By including the recoil polarization observables, a large number of response functions are obtained for a model-independent multipole analysis to extract both the dominant and small amplitudes in the $p(e,e^\prime p)\pi^0$ reaction, which are important for understanding nucleon structure and the $N$$\rightarrow$$\Delta$ transition mechanism. This thesis describes the experimental setup and the details of the absolute cross section analysis. A data-defined R-Function method was developed for the precise analysis of the small acceptance of the Hall A spectrometer. A simple and efficient analysis procedure for absolute cross section extraction with extensive use of simulation was designed and used. The extracted cross section results were parameterized for the extraction of polarized response functions from recoil polarizations. The cross section results and preliminary polarization and multipole results are presented. The $N$$\rightarrow$$\Delta$ quadrupole transition ratios $R_{EM}$ and $R_{SM}$ extracted from the differential cross sections are compared with those from the preliminary multipole analysis results.
Experiment Numbers: E91-011
Group: Hall A
Document: pdf
Accepted Manuscript:
Supporting Documents:
Supporting Datasets: