Related papers: Ground-state energy of pionic hydrogen to one loop
A systematic description of low-energy observables in light nuclei is presented. The effective field theory formalism without pions is extended to: i) predictions with next-to-leading-order (non-perturbatively) accuracy for the 4-helium…
We present a quantum mechanical study of the diatomic hydrogen $H(^{2}S)$ and oxygen $O(^{3}P)$ collision and energy transfer for its four molecular symmetry $(X^{2}\Pi, ^{2}\Sigma^{-}, ^{4}\Pi, ^{4}\Sigma^{-})$, which is important for the…
We perform highly accurate calculations of the leading order QED correction to the ground electronic state of molecular hydrogen. Numerical results are obtained for a grid of the internuclear distances $R=0-10$ au with the relative…
We model large angle intermediate energy pion-pion scattering by the pQCD two-gluon (2g) exchange contribution and discuss the onset of the dominance of the Glauber-Gribov-Landshoff (GGL) component. The pQCD 2g exchange contribution becomes…
Searching for characteristic signatures of a higher order phase transition (specifically of order three or four), we have calculated the spatial profiles and the energies of a spatially varying order parameter in one dimension. In the case…
The isotropic scattering phase shift is calculated for non-relativistic bosons interacting at low energies via an arbitrary finite-range potential in d spacetime dimensions. Scattering on a (d-1)-dimensional torus is then considered, and…
We study the self-energy amplitudes for the rho-omega meson system produced by an effective field theory model at the quark level characterized by a finite range quark-quark interaction and an isospin breaking bare quark mass difference…
In this article, we derived a rigorous lower bound on the ground-state energy for a class of one-dimensional quantum systems in deformed space with minimal coordinate and momentum uncertainties, representing the absolute minimum energy that…
Within the Euclidean effective action approach we propose criteria for the ground state of QCD. Despite a nonvanishing field strength the ground state should be invariant with respect to modified Poincar\'e transformations consisting of a…
We analyse elastic-pion nucleon scattering to fourth order in heavy baryon chiral perturbation theory, extending the third order study published in Nucl. Phys. A640 (1998) 199. We use various partial wave analyses to pin down the low-energy…
We present a new perturbative expansion for pionless effective field theory with Coulomb interactions in which at leading order the spin-singlet nucleon-nucleon channels are taken in the unitarity limit. Presenting results up to…
A report contains a review of recent theoretical investigations on kaonic atoms carried out at Stefan Meyer Institute of the Austrian Academy of Sciences. We discuss (1) a phenomenological quantum field theoretic model for bar-K N…
Hard high-energy pion-nucleus bremsstrahlung, $\pi^- +A\to\pi^- +\gamma +A$, is studied in the Coulomb region, i.e. the small-angle region where the nuclear scattering is dominated by the Coulomb interaction. Special attention is focussed…
We use an effective field theory (EFT) which contains only short-range interactions to study the dependence of a variety of three-nucleon observables on the pion mass. The pion-mass dependence of input quantities in our ``pionless'' EFT is…
Third order chiral perturbation theory accounts for the $\pi-N$ scattering phase shift data out to energies slightly below the position of the $\Delta$ resonance. The low energy constants are not accurately determined. Explicit inclusion of…
A variational technique to describe the ground and scattering states below the break-up threshold for a three-nucleon system is developed. The method consists in expanding the wave function in terms of correlated Harmonic Hyperspherical…
In this paper, we determine the exact expression for the hydrogen binding energy in the Pauli-Fierz model up to the order $O(\alpha^5\log\alpha^{-1})$, where $\alpha$ denotes the finestructure constant, and prove rigorous bounds on the…
Splitting the energy levels of a hydrogen-like atom by the electric field nonuniform at the atomic scale is studied. This situation is important for the multi-level treatment of the phenomenon of Rydberg blockade [Yu.V. Dumin, J. Phys. B,…
My talk was dedicated to the memory of Jan Stern. The brief account given below focuses on the progress achieved in the determination of the $\pi\pi$ S-wave scattering lengths, both experimentally and with light dynamical quarks on a…
We quantify the important effect of strong final state interactions in the weak $K\to2\pi$ amplitudes, using the measured $\pi$--$\pi$ phase shifts with J=0 and $I=0,2$. The final rescattering of the two pions provides a strong enhancement…