ρ-meson properties at finite nuclear density

Abstract

We calculate the momentum dependence of the ρ-meson selfenergy based on the dispersion relation for the ρN scattering amplitude f (ω) at low nuclear density. The imaginary part of f (ω) is determined from the optical theorem, while the total ρN cross section is obtained within the VDM at high energy and within the resonance model at low energy. Our numerical results indicate a sizeable broadening of the ρ-meson width in the medium especially for low relative momenta p while the real part of the ρ selfenergy is found to change its sign and to become repulsive already at momenta above 100 MeV/c. Extrapolating to nuclear saturation density ρ 0 we find a dropping of the ρ-mass for p ≈ 0 roughly in line with the QCD sumrule analysis of Hatsuda while at high energy an increase of the ρ-mass close to the prediction by Eletsky and Joffe is obtained. However, when including a broadening of the baryonic resonances in the medium, the ρmeson mass shift at p ≈ 0 becomes slightly repulsive whereas the width increases substantially.

e+e−pairs fromπ−Effenberger1, Bratkovskaya2, Cassing3 et al. 1999Phys. Rev. CSelf Cite522282View full textAdd to dashboardCite

“…3 (lower part) we also present the result of a calculation with a momentum dependent potential [18] for the vector mesons instead of the constant mass shift. This potential gives the previously used mass shift for p = 0, increases linearly with momentum and crosses zero for p = 1 GeV; for details see Ref.…”

Dilepton production in heavy-ion collisions at intermediate energies

“…While the increase of the total branching B(µ) The latter assumes an additional collision width of Γ coll ρ = 150 MeV which agrees with the estimates of refs. [4][5][6][7]. In both cases the ω width is varied between Γ tot ω = 8.4, 50, 100, 200, and 400 MeV.…”

ρ meson broadening and dilepton production in heavy ion collisions

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