Baryon-baryon scattering in a one-boson-exchange-potential approach. III. A nucleon-nucleon and hyperon-nucleon analysis including contributions of a nonet of scalar mesons

Abstract

The $\mathrm{NN}$ and $\mathrm{YN}$ results are presented from a one-boson-exchange-potential model. It consists of local potentials due to exchanges of members of the pseudoscalar, vector, and scalar-meson nonets. SU(3) relations are assumed for the axial-vector couplings of the pseudoscalar mesons, for the electric and magnetic couplings of the vector mesons, for the direct couplings of the scalar mesons, and for the hard-core radii. In the fit to $\mathrm{NN}$ the nonstrange-meson-nucleon couplings are determined. The simultaneous $\mathrm{YN}$ analysis determines the $\frac{F}{D}$ ratios and the SU(3) parameters of the scalar-meson nonet. The description of the $\mathrm{NN}$ data is good ($\frac{{\chi }^2}{\mathrm{data}}=2.17\mathrm{}$), and also of the $\Lambda p$, ${\Sigma }^{+}p$, and ${\Sigma }^{-}p$ data up to the pion production threshold. Very close to the $\Sigma N$ threshold we find a $\Lambda N$ resonance, which is dominantly in the ${}_{}{}^3{}_{}{}^{}D_1^{}{}_{}{}^{}$ wave. The $\Lambda p$ cross section is maximal just below the ${\Sigma }^{+}n$ threshold at $E=2128.918\mathrm{}$ MeV, in agreement with the experimental results of $\Lambda p$ final state interactions. The poles belonging to the $\Lambda p$ resonance are located on the second Riemann sheet at $E=2131.77\mathrm{}\pm i2.39$ MeV.