Two-pion annihilation into e+e−pairs in relativistic non-linear models

J. Pastor (1) , J.C. Caillon (1) , J. Labarsouque (1)

1 CENBG - Centre d'Etudes Nucléaires de Bordeaux Gradignan

We have studied the $\pi^{+}\pi^{-} \rightarrow e^+e^-$ process in dense and hot nuclear matter using relativistic non-linear models taking into account all scalar–vector coupling terms up to fourth order in the Lagrangian. We have determined the influence of non-linear terms on the cross section and dilepton production rate in both isoscalar and isovector channels. For one of the models considered, we have found an enhancement of the $\pi^+\pi^- \rightarrow \rho \rightarrow {e^+e^-}$ dilepton production rate in the low invariant mass region as required by the experimental data.

Mots clés: Nuclear matter; Relativistic hadronic models; Dilepton production rate

Domaines: Physique Nucléaire Théorique [nucl-th]

J. Pastor, J.C. Caillon, J. Labarsouque. Two-pion annihilation into e+e−pairs in relativistic non-linear models. Nuclear Physics A, 2005, 757, pp.456-475. ⟨10.1016/j.nuclphysa.2005.04.016⟩. ⟨in2p3-00024287⟩