2003/08/06 by S. Zschocke, Zschocke, S., O. P. Pavlenko +3
Physics and Astronomy · #FOS: Physical sciences #High Energy Physics - Phenomenology (hep-ph) #hep-ph
paper · pdf · doi:10.48550/arxiv.hep-ph/0308070
arxiv created 2003/08/06 · arxiv updated 2009/12/01
Within the Borel QCD sum rule approach at finite baryon density we study the role of the four-quark condensates for the modifications of the vector mesons ρ, ω and ϕ in nuclear matter. We find that in-medium modifications of the ρ and ω mesons are essentially dominated by the dependence of the 4-quark condensate on the nucleon density. In particular, the numerical value of a parameter (κN), which describes the strength of the density dependence of the 4-quark condensate beyond the mean-field approximation, governs the decrease of the ρ mass as a function of the density. For the ω meson the sign of the in-medium mass shift is changed by variations of κN. To study consistently the in-medium broadening of the light vector mesons we employ ρN and ωN scattering amplitudes derived recently from a covariant unitary coupled channel approach adjusted to pion- and photo-induced reactions. In contrast to the ρ and ω mesons, the in-medium mass of the ϕ meson is directly related to the chiral (strange) quark condensate. Measurements of the vector meson spectral change in heavy-ion collisions with HADES can shed light on the yet unknown density dependence of the 4-quark condensate.