Quark Generalized Partial Distribution Function Of Helicity Inversion Under Large Momentum Exchange

Feynman parton distributions, which describe the quark's and gluon's momentum dis-tributions in fast moving hadrons, are widely used in inclusive processes to represent non-perturbative effect. In exclusive processes, non-perturbative effects are described by quanti-ties such as form factors, distribution amplitudes, etc. For some diffractive processes such as Deeply Virtual Compton Scattering(DVCS) and Deeply Virtual Meson Production(DVMP),it has been proved that scattering amplitudes can be factorized into hard kernels and non-perturbative Generalized Parton Distributions(GPDs) in the regionQ2>>-t???QCD2.GPDs are introduces just twenty years ago in the study of DVCS process. It is later found to be a mixture of parton density and form factor. Using Fourier transformation GPDs can be related to 3-dimensional longitudinal momentum and transverse space parton distribu-tions. In some limits GPDs are also connected to nucleon's spin distribution. Thus GPDs provide much more complete imformation about the nucleon structure. Experimentally,DVCS and DVMP processes are the most widely used processes to probe GPDs.In large momentum transfer limit, the exchanged gluons are mostly hard gluons, thus perturbative calculation is applicable. In this thesis, we provide a leading order calculation of helicity flip quark GPD Eq(x,?, t) of nucleon in large momentum transfer limit. We do a twist expansion for the initial and final states' distribution amplitudes, the helicity can be flipped due to a unit change of orbital angular momentum. Using symmetry properties the number of diagrams need to be calculated can be reduced largely. We use spinor helicity amplitude method to calculate amplitudes. We expand and maintain the amplitudes to the first order of transverse momentum so it can be integrated with wavefunction to get twist-4 distribution amplitudes. Finally we can express Eq(x,?, t) as a convolution of a hard kernel and distribution amplitudes of initial and final nucleons. Different parts of our results can be related to helicity non-flip quark GPD Hq(x,?,t) and Pauli form factor F2. We checked this point and verified our calculation with the results of Hp(x,?, t) and F2 in literature.Our analytical result can provide valuable guidance in model construction and param-eterization of generalized parton distributions. Further numerical calculations can also be carried out in future, and then analysis of experimental data or theoretical prediction for meson production may be possible.