On the production of a narrow πNN resonance in low energy pionic DCX on He isotopes

Clement, H.; Schepkin, M.; Wagner, G.; Zaboronsky, O.

doi:10.1016/0370-2693(94)91440-0

Cited by 24 publications

(10 citation statements)

References 15 publications

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“…In principle, this would Let us note that such effects should equally renormalize the amplitude of the d ′ formation in heavier nuclei. However, it is just this amplitude (deduced from DCX transitions to discrete levels [1]) that was taken as an input to predict the d ′ production off 3 He [17].…”

Section: Discussionmentioning

confidence: 99%

Collision damping in theπ3He→d′Nreaction near the threshold

2003

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We present a simple quantum mechanical model exploiting the optical potential approach for the description of collision damping in the reaction 3 He→dЈN near the threshold, which recently has been measured at TRIUMF. The influence of the open dЈN→NNN channel is taken into account. It leads to a suppression factor of about 10 in the dЈ survival probability. Applications of the method to other reactions are outlined.

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Section: Discussionmentioning

confidence: 99%

Collision damping in theπ3He→d′Nreaction near the threshold

2003

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“…Recently, new pionic double charge exchange (DCX) (π + , π − ) data have revived the interest in dibaryon physics. DCX measurements on a number of nuclear targets ranging from 4 He to 56 Fe show a sharp peak in the excitation function at an incident pion energy T π ≃ 50 MeV and at forward angles θ L ≈ 5 • [2,3]. The location of the peak at T π ≃ 50 MeV is nearly independent of the nuclear target.…”

Section: Introductionmentioning

confidence: 96%

“…The location of the peak at T π ≃ 50 MeV is nearly independent of the nuclear target. In the 4 He -target case, the peak appears around T π ≃ 80 − 90 MeV [3] due to the additional 28 MeV of binding energy required to break up the 4 He nucleus into an unbound four-neutron final state.…”

Section: Introductionmentioning

confidence: 99%

Pionic decay of a possible d′ dibaryon

et al. 1996

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The pionic decay of a possible d ′ -dibaryon in the process d ′ → N + N + π is studied in the microscopic quark shell model and with a single-quark transition operator describing the transition q → q + π. For the d ′ with quantum numbers J P = 0 − , T = 0, we employ a six-quark shell-model wave function with a spatial s 5 p[51] X -configuration and with N = 1 harmonic oscillator quanta. It is shown that the pionic decay width depends strongly on the mass and size of the d ′ . In the case that the calculated d ′ mass is close to the experimental one a small pionic decay width of Γ π ≈ 0.04 MeV is obtained. This is an order of magnitude smaller than the experimental Γ exp π ≃ 0.5 MeV. Two possibilities to improve the calculated width are suggested. The effect of the nonstatic correction term in the transition operator and the influence of the form factor at the decay vertex on the decay width are also discussed.

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“…scattering and depends on the energy. Our calculation is done in the approximation of the hard nucleon, which allows us to evaluate the amplitude analytically and get the analytical result (14) that the sum of contributions of the pole and the contact diagrams in the Born approximation is proportional to the derivative of the one-pion exchange potential with respect to the pion mass. The calculation of the cross section for the sequential mechanism includes form factors with monopole cutoff parameter 1.3 GeV.…”

Section: (B) By Using the Lagrangiansmentioning

confidence: 99%

“…This is due to the strong distortion of the pion waves at resonance on the one hand and a variety of mechanisms that play a significant role on the other. Explaining the energy dependence of DCX has led to a diversity of proposed mechanisms, including the successive delta interaction mechanism [8,9], the meson exchange current (MEC) mechanism [10,11], the six-quark bag mechanism [12], absorption mechanisms [13], dibaryon mechanisms [14], assuming the production of the hypothetical d dibaryon, a resonance with baryon number B = 2 in the pNN subsystem, and others involving more than two nucleons.…”

Section: Introductionmentioning

confidence: 99%

Pion double charge exchange in a composite-meson model

Kezerashvili¹,

Boyko

2007

Phys. Rev. C

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The pion double charge exchange amplitude is evaluated in a composite-meson model based on the four-quark interaction. The model assumes that the mesons are two-quark systems and can interact with each other only through quark loops. To evaluate the meson exchange current contribution, the form factors of the two-pion decay modes of the ρ, σ , and f 0 mesons have been used in the calculations. The contribution of the four-quark box diagram has been taken into account as well as a contact diagram. The contributions of the ρ, σ , and f 0 mesons increase the forward scattering cross section, which depends weakly on the energy.

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On the production of a narrow πNN resonance in low energy pionic DCX on He isotopes

Cited by 24 publications

References 15 publications

Collision damping in theπ3He→d′Nreaction near the threshold

Collision damping in theπ3He→d′Nreaction near the threshold

Pionic decay of a possible d′ dibaryon

Pion double charge exchange in a composite-meson model

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