Nijmegen Soft Core Research Articles

Probing ???? Potential

We determined scattering length and effective range of ¥E¥E scattering for the ¥E¥E relative energy (M¥E¥E-2M¥E) from ¥E¥E threshold to 30 MeV/c2. Phase shift of the ¥E¥E wave function which described by scattering length and effective range was determined by fitting the ¥E¥E mass spectrum. The obtained scattering length -0.10+0.37-1.56 i¾ 0.04, and effective range 13.90 +14.35-9.13 i¾ 10.53 fm is the most consistent with the values predicted by using a series of the Nijmegen soft core models NSC97's. However the predicted values by using the Nijmegen hard core model ND (G-matrix), the extended soft core model ESC00, and the Kyoto-Niigata FSS are out of three standard deviations from the determined scattering parameters. Further, we determine ¥E¥E potential by fitting the ¥E¥E invariant mass spectrum using numerically solved ¥E¥E wave function with two-Gaussian shaped potential well. The ¥E¥E scattering parameters derived from the wave function are found to be scattering length -0.09, and effective range 29.34 fm with a maximum phase shift of 2.4 deg.

EXTRACTION OF ΛΛ SCATTERING LENGTH

We determine ΛΛ scattering parameters from a ΛΛ invariant mass spectrum that was obtained by 12 C (K-, K+ΛΛ) reaction at the KEK Proton Synchrotron. In the framework of Watson's procedure, the obtained scattering length [Formula: see text] and effective range [Formula: see text] are most consistent with the values predicted by using the Nijmegen soft core models (NSC97's). However, the predicted values by using the Nijmegen hard-core ND ( G -matrix) and the extended soft-core (ESC00) models are out of two standard deviations from the determined scattering parameters.

Formula omitted] elastic scattering cross sections in the region of [formula omitted] with a scintillating fiber active target

A hyperon–nucleon scattering experiment, KEK-PS E289, was carried out at the K2 beam line in KEK. We adopted a scintillating fiber active target as a hydrogen target for hyperon production and subsequent hyperon–nucleon scattering. We collected more data than in a previous experiment, KEK-PS E251. In this paper, the differential cross sections for Σ + p elastic scattering in the incident momentum range from 350 to 750 MeV/ c are presented and compared with theoretical predictions from the Nijmegen group (Nijmegen Soft Core 97) and the Kyoto–Niigata group (RGM-FSS and fss2).

Three-Body Cluster Effects on Single-Particle Energies in 17O and 41Ca

A method for a microscopic description of Lambda hypernuclei is formulated in the framework of the unitary-model-operator approach. A unitarily transformed hamiltonian is introduced and given in a cluster expansion form. The structure of three-body-cluster terms are discussed especially on the Lambda single-particle energy. The Lambda single-particle energies including the three-body-cluster contributions are calculated for the 0s_{1/2}, 0p_{3/2} and 0p_{1/2} states in_{Lambda}^{17}O, and for the 0s_{1/2}, 0p_{3/2}, 0p_{1/2}, 0d_{5/2}, 0d_{3/2} and 1s_{1/2} states in_{Lambda}^{41}Ca, using the Nijmegen soft-core (NSC), NSC97a-f, the Juelich A (J A) and J B hyperon-nucleon interactions. It is indicated that the three-body-cluster terms bring about sizable effects in the magnitudes of the Lambda single-particle energies, but hardly affect the Lambda spin-orbit splittings.

Unitary-model-operator approach to Λ hypernuclei

The unitary-model-operator approach (UMOA) is formulated for the description of lambda hypernuclei. The method is applied to Λ 17O. A lambda-nucleon effective interaction is derived, taking the coupling of the sigma-nucleon channel into account. The lambda single-particle energies are calculated for the 0s 1 2 , 0p 3 2 and 0p 1 2 states employing the Nijmegen soft-core (NSC), Jülich model-Ã (JÃ) and model-B̃ (JB̃) hyperon-nucleon potentials.

Hypertriton calculations with meson-theoretical hyperon-nucleon interactions

Faddeev equations for the coupled ΛNN and ΣNN systems are solved precisely for meson-theoretical nucleon-nucleon and hyperon-nucleon interactions. For the Nijmegen soft core YN potential, we obtain the hypertriton binding energy close to the experimental value. We also find that the three-body force effects caused by Λ-Σ conversion are significant and attractive.

G-matrix calculations in finite hypernuclei.

g-matrix calculations have been performed for $_{\mathrm{\ensuremath{\Lambda}}}^{5}\mathrm{He}$, $_{\mathrm{\ensuremath{\Lambda}}}^{17}\mathrm{O}$, and $_{\mathrm{\ensuremath{\Lambda}}}^{41}\mathrm{Ca}$ by solving the \ensuremath{\Lambda}-\ensuremath{\Sigma} coupled channels Bethe-Goldstone equation. The potentials employed were the Nijmegen model D and Nijmegen soft core. Calculations were performed with various choices for the Pauli-forbidden space and the energy denominator. The Nijmegen model D does a reasonable job of reproducing most experimental single-particle energies, but the calculated ground-state binding energies vary smoothly from being underbound in the $_{\mathrm{\ensuremath{\Lambda}}}^{5}\mathrm{He}$ to overbound in $_{\mathrm{\ensuremath{\Lambda}}}^{41}\mathrm{Ca}$. The Nijmegen soft core underbinds all single \ensuremath{\Lambda} states, but gives level spacings which agree with experimental values.