Φ meson self-energy in nuclear matter from ΦN resonant interactions

摘要

The Φ-meson properties in cold nuclear matter are investigated by implementing resonant ΦN interactions as described in effective approaches including the unitarization of scattering amplitudes. Several N*-like states are dynamically generated in these models around 2 GeV, in the vicinity of the ΦN threshold. We find that both these states and the non-resonant part of the amplitude contribute sizably to the Φ collisional self-energy at finite nuclear density. These contributions are of a similar strength as the widely studied medium effects from the KK cloud. Depending on model details (position of the resonances and strength of the coupling to ΦN) we report a Φ broadening up to about 40–50 MeV, to be added to the Φ → KK in-medium decay width, and an attractive optical potential at threshold up to about 35 MeV at normal matter density. The Φ spectral function develops a double peak structure as a consequence of the mixing of resonance-hole modes with the Φ quasiparticle peak. The former results point in the direction of making up for missing absorption as reported in Φ nuclear production experiments.