Pion production in proton-proton collisions in a covariant one-boson-exchange model

1999

Phys. Rev. C

Self Cite

128

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.

Section: A Cross Section Data For Beam Energy Above 2 Gevmentioning

confidence: 59%

Section: Formalismmentioning

confidence: 99%

“…We assume that the off-shell dependence of the N N * vertices are determined solely by multiplying the vertex constants by the form factors, which have the dipole form [30,43] …”

Section: (Iv) N * N σ Vertexmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

pp→pK+Λreaction in an effective Lagrangian model

1999

Phys. Rev. C

Self Cite

128

“…The aim of this paper is to investigate the dilepton production in nucleon-nucleon collisions in the beam energy range of 1-5 GeV within an effective Lagrangian model (ELM) which has been successfully applied to the description of pion and associated kaon production in pp collisions [31][32][33]. Initial interaction between two incoming nucleons is modeled by an effective Lagrangian which is based on the exchange of the π, ρ, ω and σ mesons.…”

Section: Introductionmentioning

confidence: 99%

Role of baryonic resonances in the dilepton emission in nucleon-nucleon collisions

Mosel²

2003

Phys. Rev. C

Self Cite

129

Within an effective Lagrangian model, we present calculations for cross sections of the dilepton production in proton-proton and proton-neutron collisions at laboratory kinetic energies in 1-5 GeV range. Production amplitudes include contributions from the nucleon-nucleon bremsstrahlung as well as from the mechanism of excitation, propagation, and radiative decay of ∆(1232) and N * (1520) intermediate baryonic resonances. It is found that the delta isobar terms dominate the cross sections in the entire considered beam energy range. Our calculations are able to explain the data of the DLS collaboration on the dilepton production in proton-proton collisions for beam energies below 1.3 GeV. However, for incident energies higher than this the inclusion of contributions from other dilepton sources like Dalitz decay of π 0 and η mesons, and direct decay of ρ 0 and ω mesons is necessary to describe the data.25.75. Dw, 13.30.Ce, 12.40.Yx

Strangeness production in proton—proton and proton—nucleus collisions

2006

Pramana - J Phys

In these lectures we discuss the investigation of the strange meson production in protonproton (pp) and in proton-nucleus (pA) reactions within an effective Lagrangian model. The kaon production proceeds mainly via the excitations of N * (1650), N * (1710), and N * (1720) resonant intermediate nucleonic states, in the collision of two initial state nucleons. Therefore, the strangeness production is expected to provide information about the resonances lying at higher excitation energies. For beam energies very close to the kaon production threshold the hyperon-proton final state interaction effects are quite important. Thus, these studies provide a check on the models of hyperon-nucleon interactions. The inmedium production of kaons show strong sensitivity to the self energies of the intermediate mesons.