arXiv subjects
Publications and source records attributed to J. Revai.
We studied the level shifts in the $K^- p$ system caused by the interplay of strong nuclear and long range Coulomb potentials. We observed a level rearrangement in the system and found that the $1s$ shift of kaonic hydrogen is in fact ``attractive''. In addition, we demonstrated that absorption in the strong antikaon-nucleon interaction does not destroy the level rearrangement.
New calculations of the quasi-bound state in the $K^- pp$ system using Faddeev-type equations in AGS form with coupled $\bar{K}NN$ and $πΣN$ channels were performed. A chiral $\bar{K}N$ potential together with phenomenological models of $\bar{K}N$ interaction with one- and two-pole structure of the $Λ(1405)$ resonance were used. All three potentials reproduce experimental data on low-energy $K^- p$ scattering and kaonic hydrogen with the same level of accuracy. New method of calculating the subthreshold resonance position and width in a three-body system was proposed and used together with the direct search of the resonance pole. We obtained binding energy of the $K^-pp$ quasi-bound state $\sim 32$ MeV with the chirally motivated and $47 - 54$ MeV with the phenomenological $\bar{K}N$ potentials. The width is about $50$ MeV for the two-pole models of the interaction, while the one-pole potential gives $\sim 65$ MeV width. The question of using an energy dependent potential in few-body calculations is discussed in detail. It is shown that ``self-consistent'' variational calculations using such a potential are unable to produce a reasonable approximation to the exact result.
A chirally-motivated coupled-channel $\bar{K}N$ potential, reproducing all low-energy experimental data on $K^- p$ scattering and kaonic hydrogen and suitable for using in accurate few-body calculations, was constructed. The potential was used for calculations of low-energy amplitudes of the elastic $K^- d$ scattering using Faddeev-type AGS equations with coupled $\bar{K}NN$ and $πΣN$ channels. A complex $K^- - d$ potential reproducing the three-body $K^- d$ amplitudes was constructed and used for calculation of $1s$ level shift and width of kaonic deuterium. The predicted shift $ΔE_{1s}^{K^- d} \sim -830$ eV and width $Γ_{1s}^{K^- d} \sim 1055$ eV are close to our previous results obtained with phenomenological $\bar{K}N$ potentials.
A consistent quantum mechanical calculation of partial cross-sections leading to different final states of antiprotonic helium atom was performed. For the four-body scattering wave function, corresponding to the initial state, as well as for the antiprotonic helium wave function, appearing in the final tate, adiabatic approximations was used. Calculations were carried out for a wide range of antiprotonic helium states and incident energies of the antiproton. Obtained energy dependances of some cross sections show a rich low energy structure.
The spectrum of the (L_i^3 + p-bar + 2e) four-body system was calculated in an adiabatic approach. The two-electron energies were approximated by a sum of two single-electron effective charge two-center energies as suggested in [6]. While the structure of the spectrum does not exclude the existence of long-lived states, their experimental observability is still to be clarified.
Mathematically rigorous theory of the two-body contact interaction in three dimension is reviewed. Local potential realizations of this proper contact interaction are given in terms of Poschl-Teller, exponential and square-well potentials. Three body calculation is carried out for the halo nucleus 11Li using adequately represented contact interaction.