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L.P. Kaptari (BLTP JINR Dubna & FZ Rossendorf )

L.P. Kaptari (BLTP JINR Dubna & FZ Rossendorf ). L.P. Kaptari (BLTP JINR Dubna & FZ Rossendorf). Propagation of broad meson resonances in a BUU type transport model: Application to di-electron production . H.W. Barz,B. Kampfer, Gy. Wolf, M. Zetenyi : nucl-th/0605036. Direct. Dalitz decay.

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L.P. Kaptari (BLTP JINR Dubna & FZ Rossendorf )

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  1. L.P. Kaptari (BLTP JINR Dubna & FZ Rossendorf) L.P. Kaptari (BLTP JINR Dubna & FZ Rossendorf)

  2. Propagation of broad meson resonances in a BUU type transport model: Application to di-electron production.H.W. Barz,B. Kampfer, Gy. Wolf,M. Zetenyi:nucl-th/0605036 Direct Dalitz decay Bremssrahlung

  3. “Bonn” with only four mesons The (covariant, relat. inv. ) amplitude

  4. Vertex Form Factors: 1. Bonn: 2. Electromagnetic FF’s: VMD ? (double count.) ISI + FSI (The Jost function formalism for FSI. Important only at the upper kinematical limit of the di-lectron mass) Coupling Constants (R. Shyam& U.Mosel, PRC67 (2003) 065202)

  5. Fixing parameters

  6. Gauge Invariance a) b)

  7. Results for the neutron

  8. Soft Photon Approximation:

  9. (intermediate) summary: contact terms in pn bremsstrahlung are predominant!

  10. Seagulland nucleonic currents

  11. VMD

  12. Delta contribution

  13. Tagging the pn reaction in the spectator

  14. SUMMARY • An effective model based on direct calculation of the Feynman diagrams is proposed • to parametrize, in a consistent way, the amplitudes for the dielectron production in • pp, pn and pD • Bremsstrahlung contribution is important in the whole kinematical region • of the di-electron mass and at relatively low initial energies. Without the contact • terms our results are compatible with the soft Photon Approximation and with • calculations by other authors. • Contact terms, needed to restore the gauge invariance, play a predominant role in • the bremsstrahlung amplitude in pn-reactions (in view of such circumstance, a more • consistent investigation of the recipes of restoration the GI would be valuable here). • Our approach can be easily generalized to Dp reactions. Within a covariant • Bethe Salpeter formalism by using the previously found solution of the BS equation • (with the same OBE potential) we demonstrate that detecting the spectator protons • with velocities close to the deuteron initial velocity and with momenta in the • forward direction it is possible to study experimentally the • pn sub-reaction with neutron targets.

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