Perpustakaan Digital ITB

Background: The Nijmegen extended-soft-core (ESC) models describe the nucleon-nucleon (NN), hyperonnucleon (YN), and the S = ?2 hyperon-hyperon/nucleon (YY/N) interactions in a unified way using broken SU(3) symmetry. The potentials consist of local and nonlocal potentials due to (i) one-boson exchanges (OBE), which are the members of nonets of pseudoscalar, vector, scalar, and axial-vector mesons, (ii) two pseudoscalar exchange (TPS), (iii) meson-pair exchange (MPE), and (iv) diffractive exchanges. Both the OBE and pair vertices are regulated by Gaussian form factors producing potentials with a soft behavior near the origin. Broken SU(3) symmetry serves to connect the NN, YN, and YY channels. In particular, the meson-baryon coupling constants are calculated via SU(3) using the coupling constants of the NN analysis as input. The assignment of the cutoff masses for the baryon-baryon-meson (BBM) vertices is dependent on the SU(3) classification of the exchanged mesons for OBE and a similar scheme for MPE. Purpose: The S = ?1 YN results are presented from a new version ESC16 of the ESC potential model for baryon-baryon (BB) scattering. The obtained two-body BB potentials are applied to the hyperonic many-body systems as well. Next to the standard ingredients of the ESC models, a contribution of the possible short-range repulsion due to the quark Pauli principle in the BB channels is described in a systematic way for the first time. Methods: Major novel ingredients with respect to the former versions ESC04–ESC08 are the inclusion of (i) short-range Gaussian Odderon potentials corresponding to the odd numbers of gluon exchanges next to the Pomeron potentials due to even gluon exchanges and (ii) short-range repulsion in all NN, YN, and YY channels due to Pauli-forbidden six-quark cluster (0s)6 configurations. Further new elements are (i) the extension of the JPC = 1++ axial-vector meson coupling, (ii) the inclusion of the JPC = 1+? axial-vector mesons, (iii) a completion of the 1/M corrections for the meson-pair-exchange (MPE) potentials, and (iv) the treatment of the scalar ?(861) meson within the Gell-Mann-Okubo (GMO) meson-mixing scheme and as a broad meson, like the ?(760) and (620). In contrast to ESC04, we do not consider medium strong flavor-symmetry breaking (FSB) of the coupling constants. The charge-symmetry breaking (CSB) in the p and n channels, which is an SU(2) isospin breaking, is included in the OBE, TPS, and MPE potentials. In addition to the usual set of 35 YN data and 3 + p cross sections from the recent KEK-E289 experiment, we added 11 elastic and inelastic p and three elastic ? p cross sections at higher energy. For the ESC16 model, we performed a simultaneous fit to the combined NN and YN scattering data, supplied with constraints on the YN and YY interaction originating from the G-matrix information on hypernuclei. Results: The fitting of NN dominates the determination of the couplings and the cutoff masses. Only a few parameters are strongly influenced by the YN data and by the constraints for the YY interactions following from G-matrix analyses of hypernuclei and hyperonic matter. Like in the ESC04 model, the obtained octet and singlet coupling constants and F/(F + D) ratios of the model confirm the predictions of the quark-antiquark paircreation (QPC) model with dominance of the 3P0 mechanism. This not only for the OBE couplings but also for the MPE couplings and F/(F + D) ratios. We obtained within this simultaneous fit ?2/NNdata = 1.10 and ?2/YNdata = 1.04. In particular, we were able to fit the precise experimental datum rR = 0.468 ± 0.010 for the inelastic ? p capture ratio at rest very well. Conclusions: Besides the good results for the fit to the S = ?1 scattering data, which to a large extent defines the model, also the information of hypernuclear systems, using the G-matrix method, is rather important in establishing the complete ESC model. Different versions of the model give somewhat different results for hypernuclei. The reported G-matrix calculations are performed for YN (N and N) in nuclear matter and also for some hypernuclei. The obtained well depths (U, U, U) reveal distinct features of the ESC model.