We study the excitation function of the low-lying charmonium state: $Psi$(3686) in $bar p$ Au collisions taking into account their in-medium propagation. The time evolution of the spectral functions of the charmonium state is studied with a BUU type
transport model. We calculated the excitation function of $Psi$(3686) production and show that it is strongly effected by the medium. The energy regime will be available for the PANDA experiment.
The structure of the scalar mesons has been a subject of debate for many decades. In this work we look for $bar{q}q$ states among the physical resonances using an extended Linear Sigma Model that contains scalar, pseudoscalar, vector, and axial-vecto
r mesons both in the non-strange and strange sectors. We perform global fits of meson masses, decay widths and amplitudes in order to ascertain whether the scalar $bar{q}q$ states are below or above 1 GeV. We find the scalar states above 1 GeV to be preferred as $bar{q}q$ states.
An $omega$-meson in motion with respect to a nuclear medium can couple to a $sigma$-meson through a particle-hole excitation. This coupling is large. We investigate its consequences for the width of $omega$-mesons in matter and for the s-wave annihil
ation of pions into lepton pairs which can take place in relativistic heavy ion collisions. We find that the two pion decay of $omega$-mesons, resulting from the $omega-sigma$ transition and the subsequent $2pi$ decay of the $sigma$-meson, leads to a substantial broadening of $omega$-mesons in matter and possibly to an observable effect in experiments measuring the $e^+e^-$ decay of vector mesons produced in nuclei and in relativistic heavy-ion collisions. The inverse process, the s-wave annihilation of pions into $omega$-mesons decaying into $e^+e^-$ pairs, has in general a much smaller cross section than the corresponding p-wave annihilation through $rho$-mesons and is expected to contribute rather little to the total $e^+e^-$ pair production in relativistic heavy ion collisions.
