Regge-Pole Analysis of Charge-Exchange and Hypercharge-Exchange Reactions in Pseudoscalar-Meson-Baryon Scattering

Abstract

Within the context of the vector-tensor Regge-pole exchange model, the data on charge-exchange reactions (${\ensuremath{\pi}}^{\ensuremath{-}}p\ensuremath{\rightarrow}{\ensuremath{\pi}}^{0}n,{\ensuremath{\pi}}^{\ensuremath{-}}p\ensuremath{\rightarrow}\ensuremath{\eta}n,{K}^{\ensuremath{-}}p\ensuremath{\rightarrow}{\overline{K}}^{0}n$) and hypercharge-exchange reactions [${\ensuremath{\pi}}^{\ensuremath{-}}p\ensuremath{\rightarrow}{K}^{0}\ensuremath{\Lambda}({\ensuremath{\Sigma}}^{0}),{\ensuremath{\pi}}^{+}p\ensuremath{\rightarrow}{K}^{+}{\ensuremath{\Sigma}}^{+},{K}^{\ensuremath{-}}p\ensuremath{\rightarrow}{\ensuremath{\pi}}^{0}\ensuremath{\Lambda},{K}^{\ensuremath{-}}p\ensuremath{\rightarrow}{\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\Sigma}}^{+}$] are systematically analyzed. A statistical fit is presented which provides a good quantitative description of these data. In particular, the measured differential cross sections are adequately fitted over the momentum transfer range $0\ensuremath{\le}|t|\ensuremath{\le}2.6 {(\frac{\mathrm{GeV}}{c})}^{2}$. The magnitude and sign changes of the polarization data are explained by the model with the exception of the ${\ensuremath{\pi}}^{\ensuremath{-}}p\ensuremath{\rightarrow}{\ensuremath{\pi}}^{0}n$ polarization at high energies. Predictions of immediate experimental interest include (i) near-maximal polarization in ${K}^{\ensuremath{-}}p\ensuremath{\rightarrow}{\overline{K}}^{0}n$ near $t=0$, (ii) a large polarization independent of energy for all reactions involving exchange of both a vector and tensor trajectory, (iii) differential cross sections for ${K}^{\ensuremath{-}}p\ensuremath{\rightarrow}\ensuremath{\eta}\ensuremath{\Lambda}({\ensuremath{\Sigma}}^{0})$, (iv) structure in differential cross sections near $t\ensuremath{\sim}\ensuremath{-}2.5{(\frac{\mathrm{GeV}}{c})}^{2}$, and (v) polarization for ${\ensuremath{\pi}}^{\ensuremath{-}}p\ensuremath{\rightarrow}{\ensuremath{\pi}}^{0}n$ at intermediate energies. Assuming $\mathrm{SU}(3)$ symmetry for the factorized residues, the $\frac{f}{d}$ ratios were determined for the vector and tensor nonet ${J}^{p}={\frac{1}{2}}^{+}$ baryon octet couplings.