The Reaction $pp\to p\Lambda K^{+}$ Near Threshold

Abstract

We analyze the recent total cross section data for $pp\to p\Lambda K^{+}$ near threshold measured at COSY. Using an effective range approximation for the on-shell $p\Lambda$ S-wave final state interaction we extract from these data the combination $\mathcal{K}=\sqrt{2|K_s{|}^2+|K_t{|}^2}=0.38$ fm${}^4$ of the singlet ($K_s$) and triplet ($K_t$) threshold transition amplitudes. We present an exploratory calculation of various (tree-level) vector and pseudoscalar meson exchange diagrams. Pointlike $\omega$-exchange alone and the combined (${\rho }^0,\omega ,K^{\ast +}$)-exchange can explain the experimental value of $\mathcal{K}$. The pseudoscalar meson exchanges based on a SU(3) chiral Lagrangian turn out to be too large. However, when adding ${\pi }^0$-exchange in combination with the resonant $\pi N\to S_{11}(1650)\to K\Lambda$ transition and introducing monopole form factors with a cut-off ${\Lambda }_c=1.5$ GeV one is again able to reproduce the experimental value of $\mathcal{K}$. More exclusive measurements are necessary to reveal the details of the $pp\to p\Lambda K^{+}$ production mechanism.

Accepted for publication in Eur. Phys. J. A

Cited by in corpus (9)

• Close-to-threshold Meson Production in Hadronic Interactions
• Energy dependence of the Lambda/Sigma0 production cross section ratio in proton proton interactions
• The reactions $pp\to p\Lambda K^{+}$ and $pp\to p{\Sigma }^0{K}^{+}$ near their thresholds
• Role of N*(1650) in the near threshold pp --> p Lambda K+ and pp --> p Sigma0 K+ reactions
• A relativistic two-nucleon model for $A(p,K^{+}){}_{\Lambda }B$ reaction
• Hyperon production in near threshold nucleon-nucleon collisions
• $pp\to pp\omega$ reaction near threshold
• Exclusive $K^{+}$ production in proton-nucleus collisions
• Strangeness Production in Proton-Proton Collisions Close to Threshold