Soft-core hyperon-nucleon potentials.

Journal Article · Fri Jan 01 04:00:00 EST 1999 · Phys. Rev. C

DOI:https://doi.org/10.1103/PhysRevC.59.21· OSTI ID:942334

Rijken, T A; Stoks, V G. J.; Yamamoto, Y

A new Nijmegen soft-core OBE potential model is presented for the low-energy YN interactions. Besides the results for the fit to the scattering data, which largely defines the model, we also present some applications to hypernuclear systems using the G-matrix method. The potentials are generated by the exchange of nonets of pseudoscalar, vector, and scalar mesons. As is standard in the Nijmegen soft-core models, we also include the J=0 contributions from the tensor f{sub 2},f{sub 2}',a{sub 2}, and pomeron Regge trajectories, and use Gaussian form factors to guarantee that the potentials have a soft behavior near the origin. An important innovation with respect to the original soft-core potential is the assignment of the cutoff masses for the baryon-baryon-meson (BBM) vertices in accordance with broken SU(3){sub F}, which serves to connect the NN and the YN channels. As a novel feature, we allow for medium strong breaking of the coupling constants, using the {sup 3}P{sub 0} model with a Gel-Mann-Okubo hypercharge breaking for the BBM coupling. Charge-symmetry breaking in the {Lambda}p and {Lambda}n channels is included as well. We present six hyperon-nucleon potentials which describe the available YN cross section data equally well, but which exhibit some differences on a more detailed level. The differences are constructed such that the models encompass a range of scattering lengths in the {Sigma}N and {Lambda}N channels. In all cases, we obtained {chi}{sup 2}/N{sub data}{approx}0.55 for 35 YN data. In particular, we were able to fit the precise experimental datum r{sub R}=0.468{+-}0.010 for the inelastic capture ratio at rest. For the scalar-meson mixing angle we obtained values {theta}{sub s}=37{sup o}-40{sup o}, which points to almost ideal mixing angles for the scalar q{ovr q} states. The G-matrix results indicate that the remarkably different spin-spin terms of the six potentials appear specifically in the energy spectra of {Lambda} hypernuclei.

• Research Organization: Argonne National Laboratory (ANL)
• Sponsoring Organization: ER
• DOE Contract Number: AC02-06CH11357
• OSTI ID: 942334
• Report Number(s): ANL/PHY/JA-30411
• Journal Information: Phys. Rev. C, Journal Name: Phys. Rev. C Journal Issue: 1 ; Jan. 1999 Vol. 59; ISSN 0556-2813; ISSN PRVCAN
• Country of Publication: United States
• Language: ENGLISH

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
COUPLING CONSTANTS
CROSS SECTIONS
DATA
ENERGY SPECTRA
FORM FACTORS
G MATRIX
POMERANCHUK PARTICLES
POTENTIALS
REGGE TRAJECTORIES
SCALAR MESONS
SCATTERING LENGTHS
SOFT-CORE POTENTIAL