Threshold hyperon production in proton-proton collisions at COSY-11

Abstract

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+ Lambda/Sigma0 reactions where a strong decrease of the cross section ratio close-to-threshold was observed. In order to verify models developed for the description of the Lambda and Sigma0 production we have performed the measurement on the Sigma+ hyperon and found unexpectedly that the total cross section is by more than one order of magnitude larger than predicted by all anticipated models. After the reconstruction of the kaon and neutron four momenta, the Sigma+ is identified via the missing mass technique. Details of the method and the measurement will be given and discussed in view of theoretical models.

arXiv comment7 pages, 8 figures, Phys. Lett. B in print, in the second version a minor editorial changes have been made by a native speaking proofreader and a note in proof has been added with an additional reference

References in corpus (13)

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• Total Cross Section of the Reaction pp \to pK^+ΛClose to Threshold
• Comparison of Lambda and Sigma(0) Threshold Production in Proton-Proton Collisions
• Energy dependence of the Lambda/Sigma0 production cross section ratio in proton proton interactions
• Comparison of the Near-Threshold Production of eta- and K-Mesons in Proton-Proton Collisions
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• The role of the $P_{11}(1710)$ in the $NN\to N\Sigma K$ reaction
• Role of N*(1650) in the near threshold pp --> p Lambda K+ and pp --> p Sigma0 K+ reactions
• Hyperon production in near threshold nucleon-nucleon collisions
• A method to disentangle single- and multi-meson production in missing mass spectra from quasi-free pn --> pn X reactions
• Near threshold Lambda and Sigma production in pp collisions

Cited by in corpus (26)

• On the nature of the lowest $1/2^{-}$ baryon nonet and decuplet
• K^0 and Λproduction in Ni + Ni collisions near threshold
• The role of ${\Delta }^{++\ast }(1620)$ resonances in $pp\to n{K}^{+}{\Sigma }^{+}$ reaction and its important implications
• Kaon pair production close to threshold
• A Three-Flavor Chiral Effective Model with Four Baryonic Multiplets within the Mirror Assignment
• The energy dependence of the pp->K+ n Sigma+ reaction close to threshold
• The pp->K+ n Sigma+ reaction near threshold
• Cross section of the $pp\to K^{+}{\Sigma }^{+}n$ reaction close to threshold
• The pK0Σ+ final state in proton-proton collisions
• The pp -> K^+Sigma^+n cross section from missing mass spectra
• The pp->p Lambda K+ and pp->p Sigma0 K+ reactions with chiral dynamics
• Complementary studies on $N^{\ast }$ from $e^{+}{e}^{-}$, $pp$ and $p\bar{p}$ collisions
• On the structure in the $\Lambda N$ cross section at the $\Sigma N$ threshold
• The measurement of the pp->K+ n Sigma+ reaction near threshold
• Strangeness Production Process $pp\to n{K}^{+}{\Sigma }^{+}$ within Resonance Model
• Coupled channels calculation of a pion-Lambda-nucleon quasibound state
• Reexamination of the role of the ${\Delta }^{\ast }$ resonances in the $pp\to n{K}^{+}{\Sigma }^{+}$ reaction
• On $pp\to pK\Lambda ,NK\Sigma ,pp\varphi$ -- the basic ingredients for strangeness production in heavy ion collisions
• Role of scalar dibaryon and $f_0(500)$ in the isovector channel of low-energy neutron-proton scattering
• Comparison of inclusive K+ production in proton-proton and proton-neutron collisions
• Near threshold production of the pseudoscalar mesons at the COSY-11 facility
• Three-flavor chiral effective model with four baryonic multiplets within the mirror assignment
• Meson Production at COSY-TOF and COSY-ANKE
• Strangeness Production in Hadron Reactions
• Open and Hidden Strangeness Production in Nucleon-Nucleon Collisions
• Strangeness production from pp collisions