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$e^+e^-$ pairs from $π^-$A reactions

Th. Weidmann·E. L. Bratkovskaya·W. Cassing·U. Mosel
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Abstract

We present a dynamical study of $e^+e^-$ production in $π^-$A reactions at 1.3 and 1.7 GeV on the basis of the Coupled-Channel-BUU approach. The contributions from vector mesons ($ρ,ω$) are calculated taking into account the collisional broadening effect and are compared to background sources in the dilepton spectrum from the Dalitz decays of $ω$ and $η$ mesons produced in the reaction. Two possible scenarios for the medium modifications of the vector mesons are investigated, i.e. the 'dropping mass' scheme for the $ρ$ and $ω$ and a momentum dependent $ρ$-meson spectral function that includes the polarization of the $ρ$-meson due to resonant $ρ-N$ scattering.

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Th. Weidmann, E. L. Bratkovskaya, W. Cassing, U. Mosel. 1998-12-03. $e^+e^-$ pairs from $π^-$A reactions. https://doi.org/10.1103/physrevc.59.919

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