2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/191080We discuss medium modification of the rho meson originating from its coupling to in medium quasi-pions and delta-hole states. This medium effect leads to a marked structure of the rho meson strength function in the $500 MeV$ invariant mass region. We suggest that this effect may provide an explanation of the structure observed by the DLS collaboration in the $Ca+Ca/C+C$ ratio at $1 GeV/u$.5 pages and 3 figures, LatexNuclear Theorytext