The role of the Δ (1920) resonance for kaon production in heavy ion collisions

Tsushima, K.; Huang, S.W.; Faessler, Amand

doi:10.1016/0370-2693(94)90971-7

Cited by 110 publications

(136 citation statements)

References 37 publications

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“…Recently, Tsushima et al [53] studied kaon production in πN and π∆ interactions in the resonance model. The kaon is produced mainly in the s-channel processes from the decay of baryon resonances such as N (1650), N (1710), N (1720), and ∆(1920).…”

Section: Kaon Production In Pion-baryon Interactionsmentioning

confidence: 99%

Kaons in dense matter, kaon production in heavy-ion collisions, and kaon condensation in neutron stars

1997

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The recent past witnesses the growing interdependence between the physics of hadrons, the physics of relativistic heavy-ion collisions, and the physics of compact objects in astrophysics. A notable example is the kaon which plays special roles in all the three fields. In this paper, we first review the various theoretical investigations of kaon properties in nuclear medium, focusing on possible uncertainties in each model. We then present a detailed transport model study of kaon production in heavy-ion collisions at SIS energies. We shall discuss especially the elementary kaon and antikaon production cross sections in hadron-hadron interactions, that represent one of the most serious uncertainties in the transport model study of particle production in heavy-ion collisions. The main purpose of such a study is to constrain kaon in-medium properties from the heavy-ion data. This can provide useful guidances for the development of theoretical models of the kaon in medium. In the last part of the paper, we apply the kaon in-medium properties extracted from heavy-ion data to the study of neutron star properties. Based on a conventional equation of state of nuclear matter that can be considered as one of the best constrained by available experimental data on finite nuclei, we find that the maximum mass of neutron stars is about 2M⊙, which is reduced to about 1.5M⊙ once kaon condensation as constrained by heavy-ion data is introduced.pacs: 25.75. Dw, 97.60.Jd, 26.60.+c, 24.10.Lx

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Section: Kaon Production In Pion-baryon Interactionsmentioning

confidence: 99%

Kaons in dense matter, kaon production in heavy-ion collisions, and kaon condensation in neutron stars

1997

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Section: Pacsmentioning

confidence: 99%

“…Their properties are sum-1 marized in Table 1. Most of the coupling constants, cut-off parameters and form factors have been fixed by the previous studies for the πN → Y K (Y = Σ, Λ) reactions [6,8].Together with the quantities newly appearing in the pp → pΛK + reaction [4], we summarize the parameters of our model used for this study in Table 2.Here, we should comment that the main features of our results are very similar to those of Fäldt and Wilkin [5]. In particular, the π-meson exchange is dominant at energies close to the reaction threshold.…”

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confidence: 99%

“…First, with the same set of parameters, one should reproduce simultaneously the experimental data for the πN → ΛK reaction. Indeed, the approach of the resonance model made previously [4] and again here uses the same parameter set consistently with that used for the study of the πN → ΛK reactions as well as the πN → ΣK reactions [6,8]. Thus, our study for this reaction does not have much freedom to vary the parameters, nor to introduce new parameters.…”

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A clue to the mechanism of ΛK+ production in pp-reactions

1998

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We analyse the pp → pΛK + total cross section data which were recently measured by the COSY-11 collaboration at an energy 2 MeV above the reaction threshold. Our analysis suggests that the measurement of the invariant mass spectrum for the ΛK + at energies around 100 MeV above the threshold can provide a new constraint on the theoretical calculations for this reaction. In particular, the measurement can give a clue as to whether the reaction is dominated by resonance excitation or not. Thus, it should contribute to further understanding of the strangeness production mechanism. We show the invariant mass spectra for the ΛK + system in these optimal kinematic conditions calculated by several approaches, and demonstrate that our suggestion is experimentally feasible. : 13.75, 25.40, 14.20.G, 24.10 Keywords: Kaon production, Proton proton collision, Baryon resonance, One boson exchange, ΛK + invariant mass spectrum * Supported in part by the Forschungszentrum Jülich, and the Australian Research Council † sibirt@theorie.physik.uni-giessen.de ‡ ktsushim@physics.adelaide.edu.au § athomas@physics.adelaide.edu.au 0 Recently the COSY-11 Collaboration [1] measured the total cross section for the reaction, pp → pΛK + , at energy 2 MeV above the reaction threshold. The data were compared with the theoretical models which are presently available for this reaction [2,3,4,5]. Among them, both the predictions of Sibirtsev [2] and Li and Ko [3] could reproduce the experimental data at this energy well only with the inclusion of pion and kaon exchanges, but without the inclusion of any resonances which are observed to decay to the ΛK + channel. Moreover, it was found [2,3] that the dominant contribution to the pp → pΛK + reaction comes from the K-exchange mechanism. Alternatively, the study of Fäldt and Wilkin [5] which was made analogous to the pp → ppη reaction with a nonrelativistic treatment including the final state interaction, suggests that the total cross sections for the pp → pΛK + reactions at energies only slightly above threshold can possibly be explained by one pion-exchange followed by N ⋆ (1650) resonance excitation. Furthermore, they claim that these two ingredients alone are almost enough to describe the data. One of their motivations was to study whether the same type of meson exchange model could be capable of explaining simultaneously the near-threshold η and K production data -one pion exchange followed by N ⋆ (1650) resonance excitation for the present case. PACSIn Ref.[4], within the resonance model, we performed the most detailed study of kaon production in proton-proton collisions with a full relativistic treatment. This included the mechanism adopted by Fäldt and Wilkin [5] as just one of the processes in evaluating the total cross sections. However, it has turned out that our calculation underestimates the data [1] at energy 2 MeV above the threshold -as shown in Fig. 1. It underestimates the experimental data from COSY by about a factor of 2, although it reproduces the existing data fairly wel...

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“…Furthermore, it has been argued that the existing high energy data can be well reproduced considering only the single pion-exchange process [18,19] since the contribution of the K-meson exchange amplitude can be compensated by various parameters of the model. In the resonance model [21] of the strangeness production in pp collisions, the π, η, and ρ-meson exchanges are included and the K + meson production proceeds via the excitation of the N * (1650), N * (1710) and N * (1720) resonances [22,24]. However, the terms in the total amplitude involving the interference of various resonance contributions are neglected in these calculations.…”

Section: Introductionmentioning

confidence: 99%

pp→pK+Λreaction in an effective Lagrangian model

Shyam

1999

Phys. Rev. C

128

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We investigate the pp → pK + Λ 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 the exchange of π, ρ, ω and σ mesons and the ΛK + production proceeds via the excitation of the N * (1650), N * (1710), N * (1720) baryonic resonances. The parameters of the model at the nucleon-nucleon-meson vertices are determined by fitting the elastic nucleon-nucleon scattering with an effective interaction based on the exchange of these four mesons, while those at the resonance vertices are calculated from the known decay widths of the resonances as well as the vector meson dominance model. Available experimental data is described well by this approach. The one-pion-exchange diagram dominates the production process at both higher and lower beam energies. The ρ and ω meson exchanges make negligible contributions. However, the σ-exchange processes contribute substantially to the total cross sections at lower beam energies. The excitation of the N * (1710) and N * (1650) resonances dominate this reaction at beam momenta above and below 3 GeV/c respectively. The interference among the amplitudes of various resonance excitation processes is significant. For beam energies very close to the K + production threshold the hyperon-proton final state interaction effects are quite important. The data is selective about the model used to describe the low energy scattering of the two final state baryons.

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The role of the Δ (1920) resonance for kaon production in heavy ion collisions

Cited by 110 publications

References 37 publications

Kaons in dense matter, kaon production in heavy-ion collisions, and kaon condensation in neutron stars

Kaons in dense matter, kaon production in heavy-ion collisions, and kaon condensation in neutron stars

A clue to the mechanism of ΛK+ production in pp-reactions

pp→pK+Λreaction in an effective Lagrangian model

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