Spin Polarization in Electron Scattering off Few  Nuclei.
Abstract
The purpose of this investigation is twofold: to establish a relativistic formalism for the description of inelastic, twobody, coincidence, electron scattering off fewbody nuclei with spins one half or one, and to investigate the role of strangenessinduced weakneutral current matrix elements of fewbody nuclei and parityviolating admixtures to the nucleon wave function in elastic, parity violating electronnucleus scattering. Helicity formalism was used in the formulation of comprehensive treatments of all singlepolarization observables in scalar and pseudoscalar electroproduction off spin one half targets and all single and doublepolarization observables in deuteron twobody photo and electrodisintegration, from a unified standpoint. A discussion of necessary and sufficient measurements needed for a complete determination of all transition amplitudes is given. Wigner rotation of the recoil polarization coincidence electrodisintegration and electroproduction structure functions due to the boost from the centreofmass to the lab frame are calculated. Inequalities among polarized spin one half target and unpolarized ejectile as well as unpolarized target and polarized spin one half ejectile coincidence structure functions due to the positivity of the polarized coincidence cross section are derived for arbitrary reactions with spin one half targets and ejectiles. It is shown how to separate strangenessinduced form factors of the nucleon from elastic, parityviolating electron scattering data. A parityviolating quarkquark potential is derived by a nonrelativistic reduction of oneW^+/,Z^circ exchange Feynman diagrams. The abnormal parity admixture in the nucleon wave function is calculated using first order perturbation theory in a nonrelativistic quark model with harmonic oscillator wave functions and the lowest lying negative parity nucleon resonances. The contribution of these parity admixtures to the elastic parityviolating electromagnetic current matrix element of the nucleon is evaluated. Special attention is paid to the gauge invariance of the calculation: gauge invariance preserving twobody quark parityviolating electromagnetic current is constructed. It is shown that the elastic parityviolating electromagnetic current matrix element has the correct behaviour in the longwavelength limit only if all abnormal parity admixtures to the wave function are included. A new definition of the parityviolating, timereversal preserving elastic electromagnetic current matrix element, which automatically satisfies the threshold theorem, is given. An exact argument, based on closure, about the contribution of all parity admixtures to the elastic parityviolating electromagnetic current matrix element is established. The complete elastic parityviolating electromagnetic current matrix element of the nucleon is shown to vanish identically, to first order in G_ F, in all nonrelativistic quark models with spin and isospin independent, local, strong quarkquark potentials. ftn*Originally published in DAI, Vol. 52 No. 3. Reprinted here with corrected bibliographic information.
 Publication:

Ph.D. Thesis
 Pub Date:
 January 1990
 Bibcode:
 1990PhDT.......140D
 Keywords:

 Physics: Nuclear