Related papers: Learning from Dispersive Effects in the Nucleon Po…
This PhD thesis is devoted to the low-energy structure of the nucleon (proton and neutron) as seen through electromagnetic probes, e.g., electron and Compton scattering. The research presented here is based primarily on dispersion theory…
We employ the chiral nucleon-nucleon potential derived using the method of unitary transformation up to next-to-next-to-leading order (NNLO) to study bound and scattering states in the two-nucleon system. The predicted partial wave phase…
Background: Elastic scattering is probably the main event in the interactions of nucleons with nuclei. Even if this process has been extensively studied in the last years, a consistent description, i.e. starting from microscopic two- and…
We formulate microscopic neutron-nucleus optical potentials from many-body perturbation theory based on chiral two- and three-body forces. The neutron self energy is first calculated in homogeneous matter to second order in perturbation…
We use chiral perturbation theory to compute the effective nucleon propagator in an expansion about low density in the chiral limit. We neglect four-nucleon interactions and focus on pion exchange. Evaluating the nucleon self-energy on its…
We introduce a new and well defined power counting for the effective field theory describing nucleon-nucleon interactions. Because of the large NN scattering lengths it differs from other applications of chiral perturbation theory and is…
The simple model describing charge independence and charge symmetry breaking of the pion-nucleon coupling constant is proposed. The model, which has simple physical meaning and foundation, suggests directly proportional dependence of the…
We present a fit of the spin-independent electromagnetic polarisabilities of the proton to low-energy Compton scattering data in the framework of covariant baryon chiral effective field theory. Using the Baldin sum rule to constrain their…
We present a calculation of the fourth-order (NLO) contribution to spin-dependent Compton scattering in heavy-baryon chiral perturbation theory, and we give results for the four spin polarisabilities. These results have been presented…
We report on a chiral effective field theory calculation of Compton scattering from the proton. Our calculation includes pions, nucleons, and the Delta(1232) as explicit degrees of freedom. It uses the "delta expansion", and so implements…
We study the energy dependence of the total and diffractive neutrino-nucleon and neutrino-nucleus cross sections at very high energies. The calculation employs the QCD dipole model and the small-$x$ nonlinear Balitsky-Kovchegov evolution.…
Extending a recent suggestion for hyperon form factors to the nucleon case, dispersion theory is used to relate the low-energy vector-isovector form factors of the nucleon to the pion vector form factor. The additionally required input,…
Low energy Compton scattering allows the investigation of one of the fundamental properties of the nucleon -- how its internal structure deforms under an applied electromagnetic field. We review recent developments in the investigation of…
I present the results obtained for several observables in the two-nucleon sector using effective field theory with KSW power-counting and dimensional regularization. In addition to the phase shifts for nucleon-nucleon scattering, several…
Low-energy Compton scattering off the proton is used for determination of the proton polarizabilities. However, the present empirical determinations rely heavily on the theoretical description(s) of the experimental cross sections in terms…
We report observables for elastic Compton scattering from $^3$He in Chiral Effective Field Theory with an explicit $\Delta(1232)$ degree of freedom ($\chi$EFT) for energies between 50 and 120 MeV. The $\gamma\,{}^3$He amplitude is complete…
We report on a calculation of the nucleon-nucleon scattering amplitudes in the $^1S_0$ and $^3S_1$-$^3D_1$ channels at next-to-next to leading order using a recently proposed non-relativistic chiral effective theory, which includes dibaryon…
The spin polarizabilities of the nucleon describe how the spin of the nucleon responds to an incident polarized photon. The most model-independent way to measure the nucleon spin polarizabilities is through polarized Compton scattering.…
Nucleon transfer reactions in low-energy deuteron-deuteron scattering are described by solving exact four-particle equations in momentum space. The Coulomb interaction between the protons is included using the screening and renormalization…
Recently developed chiral effective field theory models provide excellent descriptions of the bulk characteristics of finite nuclei, but have not been tested with other observables. In this work, densities from both relativistic…