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Constraints on vector mesons with finite momentum in nuclear matter

Bengt Friman·Su Houng Lee·Hungchong Kim
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Abstract

Using the QCD operator product expansion, we derive the real part of the transverse and longitudinal vector-vector correlation function with the quantum numbers of the rho and omega mesons to leading order in density and three momentum (q^2) for energy $ω^2 --> -\infty $. The operator product expansion provides, through the Borel transformed energy dispersion relation, a model independent constraint for the momentum dependence of the vector meson spectral density in nuclear matter. Existing model calculations for the dispersion effect of the rho meson, where the vector-meson nucleon scattering amplitude is obtained by resonance saturation in the s-channel, in general violate this constraint. We trace this to an inconsistent choice for the form factor of the $ΔNρ$ vertex. With a consistent choice, where both the form factor and the coupling constant are obtained from the Bonn potential, the contribution of the $Δ$ is substantially reduced and we find good agreement with the constraint equation. We briefly comment on the implications of our result for attempts to interpret the enhancement of low-mass dileptons in heavy-ion collisions.

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Bengt Friman, Su Houng Lee, Hungchong Kim. 1999-03-30. Constraints on vector mesons with finite momentum in nuclear matter. https://doi.org/10.1016/s0375-9474(99)00171-2

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