Related papers: On the $\Lambda$ to $\Sigma^0$ ratio from proton-p…
The energy dependence of the reactions pp -> p Lambda K+ and pp -> p Sigma0 K+ and the ratio R(Lambda/Sigma0} is studied in a constituent quark-gluon model, including the excitation of the baryon resonances N*(1650), N*(1710) and N*(1720)…
The production of the Lambda and Sigma0 hyperons has been measured via the pp->pK+Lambda / Sigma0 reaction at the internal COSY-11 facility in the excess energy range between 14 and 60 MeV. The transition of the Lambda/Sigma0 cross section…
The cross sections of the reaction $pp \to N K Y$ for $K^+$ or $K^0$ mesons and $\Lambda$ or $\Sigma$ hyperons are calculated within the boson exchange model including pion and kaon exchange diagrams. We analyze the dependence of the…
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…
This paper reports results on simultaneous measurements of the reaction channels pp -> pK+\Lambda and pp -> pK+\Sigma^0 at excess energies of 204, 239, and 284 MeV (\Lambda) and 127, 162, and 207 MeV (\Sigma^0). Total and differential cross…
A model calculation for the reactions $pp\to p\Lambda K^+$ and $pp\to N\Sigma K$ near their thresholds is presented. It is argued that the experimentally observed strong suppression of $\Sigma^0$ production compared to $\Lambda$ production…
Inclusive K+ production in proton-proton collisions has been measured at a beam energy of 2.16 GeV using the COSY-ANKE magnetic spectrometer. The resulting spectrum, as well as those corresponding to K+ p and K+ pi+ correlated pairs, can…
Measurements of the near threshold Lambda and Sigma0 production via the pp-->pK+Lambda/Sigma0 reaction at COSY--11 have shown that the Lambda/Sigma0 cross section ratio exceeds the value at high excess energies Q>=300 MeV by an order of…
We show that the recently measured asymmetry in helicity-angle spectra of the Lambda-hyperons produced in the reaction pp -> K^+Lambda p reaction and the energy dependence of the total pp -> K^+Lambda p cross section can be explained…
The reactions $pp\to p\Lambda K^+$ and $pp\to p\Sigma^0K^+$ are studied near their thresholds. The strangeness production process is described by the $\pi$- and $K$ exchange mechanisms. Effects from the final state interaction in the…
Exclusive data on the reactions pp -> ppK+K- and pp -> pK+ Lambda/Sigma0 have been taken at the cooler synchrotron COSY close to threshold. At equal excess energies, an enhancement of the Lambda/Sigma0 ratio by one order of magnitude has…
We present results for the $p p \to p p \omega$ reaction studied by considering two different scenarios: with and without the inclusion of nucleon resonance excitations. The recently measured angular distribution by the COSY-TOF…
Sigma+ hyperon production was measured at the COSY-11 spectrometer via the p p --> n K+ Sigma+ reaction at excess energies of Q = 13 MeV and Q = 60 MeV. These measurements continue systematic hyperon production studies via the p p --> p K+…
We conducted a theoretical study on the process $\Sigma^{+} p \to\Lambda a_0^{+} p$ based on an effective Lagrangian approach. This model encompasses the excitation of intermediate states leading to the production of $\Delta(1920)$ through…
We study the mechanism of the associated Lambda-kaon and Sigma-kaon production in nucleon-nucleon collisions over an extended range of near threshold beam energies within an effective Lagrangian model, to understand of the new data on pp…
The cross sections for the reactions of the strange production p + p -> p + Lambda + K^+ and p + p -> p + Sigma^0 + K^+ near thresholds of the final states p Lambda K^+ and p Sigma^0 K^+ are calculated in the effective Lagrangian approach.…
The $\gamma p \to K^+ \pi^0 \Lambda$ and $\gamma p \to K^+ \pi \Sigma $ reactions are studied in the kinematic region where the $\pi^0 \Lambda$(1116) and $\pi\Sigma$(1192) pairs originate dominantly from the decay of the $\Sigma$(1385) and…
The experimental data from the 2m propane bubble chamber have been analyzed for pC$\to \Lambda(K^0_s)X$ reactions at 10 GeV/c. The estimation of experimental inclusive cross sections for $\Lambda$ and $K^0_s$ production in the p$^{12}C$…
Threshold measurements of the associated strangeness production reactions pp --> p K(+) Lambda and pp --> p K(+) Sigma(0) are presented. Although slight differences in the shapes of the excitation functions are observed, the most remarkable…
We investigate the $pp \to pK^{+}\Lambda$ reaction within an effective Lagrangian model where the contributions to the amplitudes are taken into account within the tree level. The initial interaction between the two nucleons is modeled by…