Modern Nuclear Force Predictions for the α Particle

We present new calculations of the α particle which are based on the most modern nucleon-nucleon interactions alone and combined with the Tucson-Melbourne or the Urbana IX three-nucleon interaction. Results for the binding energies and some properties of the wave function are given. On that phenomenological level little room is left for the action of a possible four-nucleon force

The Hypernuclei Λ4He and Λ4H: Challenges for Modern Hyperon-Nucleon Forces

The hypernuclei Λ4He and Λ4H provide important information on the hyperon-nucleon interaction. We present accurate Faddeev-Yakubovsky calculations for the Λ separation energies of the 0+ ground and the 1+ excited states based on the Nijmegen SC YN interactions. We explicitly take the Σ admixture into account. Mass differences of the baryons and the charge dependence of the interaction are considered. The results show that the Nijmegen models cannot predict all separation energies simultaneously hinting to failures of the current interaction models. It is pointed out that the differences of the Λ separation energies of Λ4He and Λ4H are interesting observables to probe the YN interaction models

The Hypernuclei Λ4He and Λ4H: Challenges for Modern Hyperon-Nucleon Forces

The hypernuclei Λ4He and Λ4H provide important information on the hyperon-nucleon interaction. We present accurate Faddeev-Yakubovsky calculations for the Λ separation energies of the 0+ ground and the 1+ excited states based on the Nijmegen SC YN interactions. We explicitly take the Σ admixture into account. Mass differences of the baryons and the charge dependence of the interaction are considered. The results show that the Nijmegen models cannot predict all separation energies simultaneously hinting to failures of the current interaction models. It is pointed out that the differences of the Λ separation energies of Λ4He and Λ4H are interesting observables to probe the YN interaction models

Search for Three-Nucleon Force Effects in Two-Body Photodisintegration of 3He(3H) and in the Time Reversed Proton-Deuteron Radiative Capture Process

Faddeev calculations have been performed for nucleon-deuteron photodisintegration of 3He(3H) and proton-deuteron radiative capture. The bulk of the results is based on the AV18 nucleon-nucleon force and the Urbana IX three-nucleon force together with explicit exchange currents or applying the Siegert approach. Three-nucleon force effects are predicted for both processes and supported by most of the data.Comment: 21 pages, 8 figures, modified version with changed figures, conclusions unchanged, to appear in Phys.Rev.

Lorentz boosted NN potential for few-body systems: Application to the three-nucleon bound state

A Lorentz boosted two-nucleon potential is introduced in the context of equal time relativistic quantum mechanics. The dynamical input for the boosted nucleon-nucleon (NN) potential is based on realistic NN potentials, which by a suitable scaling of the momenta are transformed into NN potentials belonging to a relativistic two-nucleon Schrödinger equation in the c.m. system. This resulting Lorentz boosted potential is consistent with a previously introduced boosted two-body t matrix. It is applied in relativistic Faddeev equations for the three-nucleon bound state to calculate the 3H binding energy. Like in previous calculations the boost effects for the two-body subsystems are repulsive and lower the binding energy

A novel treatment of the proton-proton Coulomb force in elastic proton-deuteron Faddeev calculations

We propose a novel approach to incorporate the proton-proton (pp) Coulomb force into the three-nucleon (3N) Faddeev calculations. The main new ingredient is a 3-dimensional screened pp Coulomb t-matrix obtained by a numerical solution of the 3-dimensional Lippmann-Schwinger (LS) equation. We demonstrate numerically and provide analytical insight that the elastic proton-deuteron (pd) observables can be determined directly from the resulting on shell 3N amplitude increasing the screening radius. The screening limit exists without the need of renormalisation not only for observables but for the elastic pd amplitude itself.Comment: 33 pages, 4 eps figures. New figure with a description in the Section V and minor text changes have been added. The physical conclusions remain unchange

Proton-proton scattering without Coulomb force renormalization

We demonstrate numerically that proton-proton (pp) scattering observables can be determined directly by standard short range methods using a screened pp Coulomb force without renormalization. In examples the appropriate screening radii are given. We also numerically investigate solutions of the 3-dimensional Lippmann-Schwinger (LS) equation for a screened Coulomb potential alone in the limit of large screening radii and confirm analytically predicted properties for off-shell, half-shell and on-shell Coulomb t-matrices. These 3-dimensional solutions will form a basis for a novel approach to include the pp Coulomb interaction into the 3N Faddeev framework.Comment: 22 pages, 13 eps figure

Effective Interactions for the Three-Body Problem

The three-body energy-dependent effective interaction given by the Bloch-Horowitz (BH) equation is evaluated for various shell-model oscillator spaces. The results are applied to the test case of the three-body problem (triton and He3), where it is shown that the interaction reproduces the exact binding energy, regardless of the parameterization (number of oscillator quanta or value of the oscillator parameter b) of the low-energy included space. We demonstrate a non-perturbative technique for summing the excluded-space three-body ladder diagrams, but also show that accurate results can be obtained perturbatively by iterating the two-body ladders. We examine the evolution of the effective two-body and induced three-body terms as b and the size of the included space Lambda are varied, including the case of a single included shell, Lambda hw=0 hw. For typical ranges of b, the induced effective three-body interaction, essential for giving the exact three-body binding, is found to contribute ~10% to the binding energy.Comment: 19 pages, 9 figures, submitted to PR

Low-momentum nucleon-nucleon interaction and its application to few-nucleon systems

Low-momentum nucleon-nucleon interactions are derived within the framework of a unitary-transformationtheory, starting with realistic nucleon-nucleon interactions. A cutoff momentum L is introduced to specify aborder between the low- and high-momentum spaces. By Faddeev-Yakubovsky calculations the lowmomentuminteractions are investigated with respect to the dependence of ground-state energies of 3H and 4Heon the parameter L. It is found that we need the momentum cutoff parameter Lù5 fm−1 in order to reproducesatisfactorily the exact values of the binding energies for 3H and 4He. The calculation with L=2 fm−1 recommendedby Bogner et al. leads to considerable overbinding at least for few-nucleon systems