e+e- production in NN collisions at 1.25 GeV


Di-electron production in N+N collisions at Ekin < 5 GeV/u was studied previously by the DLS collaboration [1] and have been available for about 10 years, although with limited statistics and mass resolution. Microscopic transport calculation, hovewer, never succeeded to explain the experimental data satisfactory until a strong bremsstrahlung contribution in n+p interactions has been recently predicted within the framework of a covariant One Boson Exchange (OBE) model [2]. The authors choose the free parameters of their theory similar to the ones used in [3], but the restoration of the gauge invariance (for n+p) has been realized in a different way. This leads to different types of the form factors and quite different results. Indeed, it is found to differ by a factor of 4 for n+p interactions, but also by a factor of about 2 for p+p reactions at 1 GeV kinetic beam energy compared to the ones of Ref. [3]. As the NN bremsstrahlung process as included in the new OBE calculations from Kaptari et al. [2] is widely discussed in context with the interpretation of the C+C data, we should have a closer look on the comparison of these calculations to the HADES data for p+p and n+p interactions.

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Cite this paper

@inproceedings{Frhlich2010eePI, title={e+e- production in NN collisions at 1.25 GeV}, author={Ingo Fr{\"{o}hlich and T . Galatyuk}, year={2010} }