Doctor of Philosophy (Ph.D.)
Carl E Carlson
The AdS/CFT correspondence relates a strongly coupled gauge theory in four dimensional space-time with a weakly coupled gravity theory in five dimensional space-time. This correspondence provides a way to access the strongly coupled regime of a gauge theory via a perturbative approach in its gravity dual theory. In this dissertation, the gravity dual of Quantum Chromodynamics (QCD) is discussed. The so-called bottom-up approach (AdS/QCD) successfully reproduces the low energy observables at 10-20% accuracy.;An AdS/QCD model with two flavors of quarks is considered, assuming isospin symmetry. Pions and rho mesons masses and decay constants are obtained. We calculate the stress tensor, or energy-momentum tensor, form factors. Mesons appear strikingly more compact measured by the gravitational form factor than by the electromagnetic form factor.;Extension of the model to three flavors of quarks, incorporating quarks with differing masses (including the strange quark), is also considered. Dynamical properties of mesons such as electromagnetic form factors, strangeness-changing form factors, and gravitational form factors are obtained from 3-point function calculations. The results agree well with experimental data (when available) and with calculations from other methods (when available).;Electromagnetic and gravitational form factors for baryons are calculated, in a scheme where the baryons are treated as independent particles in AdS space. The form factors were calculated both in the case of so called hard-wall and soft-wall model. The simplest fermion Lagrangian for the five dimensional curved space does not contribute to the F2 form factor unless one adds a Pauli term, which also contributes to the F1 form factor.
© The Author
Abidin, Zainul, "Hadron structure from holographic QCD" (2010). Dissertations, Theses, and Masters Projects. Paper 1539623570.