QCD sum rules, scattering length, and vector mesons in the nuclear medium

Hatsuda, Tetsuo; Lee, Su Houng; Shiomi, H.

doi:10.1103/physrevc.52.3364

Cited by 88 publications

(186 citation statements)

References 24 publications

(60 reference statements)

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“…However, further studies have revealed that for the case of a nuclear medium there is instead a rather large model dependence in the possible parameterizations which enter the hadronic side of the sum rules. In [5,6] it has been "predicted" that the mass of the ρ-meson should drop in a nuclear medium. The type of parameterization for the spectral function of the ρ-meson was adopted from the vacuum case: a state with practically negligible width (in the vacuum this approach is very successful [2]).…”

Section: Introductionmentioning

confidence: 99%

QCD sum rules at finite density in the large- limit: the coupling of the ρ-nucleon system to the

Leupold¹,

Post²

2005

Nuclear Physics A

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QCD sum rules are studied for the vector-isovector current at finite baryon density in the limit of large number of colors Nc. For the condensate side it is shown that in this limit the four-quark condensate factorizes also for the finite density case. At the hadronic side the medium dependence is expressed in terms of the current-nucleon forward scattering amplitude. Generalizing vector meson dominance we allow for a direct coupling of the current to the nucleon as well as a coupling via the ρ meson. We discuss the Nc dependence of (a) modifications of the pion cloud of the ρ meson, (b) mixing with other mesons (in particular a1 and ω) and (c) resonance-hole excitations R N −1 . We show that only the last effect survives in the large-Nc limit. Saturating the sum rules with a simple hadronic ansatz which allows for the excitation of the D13(1520) we determine the coupling of the latter to the ρ-nucleon and the photon-nucleon system. These couplings are hard to determine from vacuum physics alone.

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Section: Introductionmentioning

confidence: 99%

QCD sum rules at finite density in the large- limit: the coupling of the ρ-nucleon system to the

Leupold¹,

Post²

2005

Nuclear Physics A

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“…A number of analyses [8][9][10][11] have found that the masses of ρ and ω resonances decrease in nuclear medium 1 . In Refs.…”

Section: Introductionmentioning

confidence: 99%

ρ−ωmixing in asymmetric nuclear matter via a QCD sum rule approach

2000

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We evaluate the operator product expansion (OPE) for a mixed correlator of the isovector and isoscalar vector currents in the background of the nucleon density with intrinsic isospin asymmetry [i.e. excess of neutrons over protons] and match it with its imaginary part, given by resonances and continuum, via the dispersion relation. The leading density-dependent contribution to ρ − ω mixing is due the scattering term, which turns out to be larger than any density dependent piece in the OPE. We estimate that the asymmetric density of nn − np ∼ 2.5 × 10 −2 fm 3 induces the amplitude of ρ − ω mixing, equal in magnitude to the mixing amplitude in vacuum, with the constructive interference for positive and destructive for negative values of nn − np. We revisit sum rules for vector meson masses at finite nucleon density to point out the numerical importance of the screening term in the isoscalar channel, which turns out to be one order of magnitude larger than any density-dependent condensates over the Borel window. This changes the conclusions about the density dependence of mω, indicating ∼ 40 MeV increase at nuclear saturation density.

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“…QCD sum rule analysis showed that the mass of the ρ-meson drops fast with density using this ansatz, see e.g. [13,15,16,17]. The density dependence of the in-medium meson mass is also almost the same if one calculates the in-medium mass from the change of the bare ρ-meson mass using an an effective meson Lagrangian, see Fig.…”

Section: Resultsmentioning

confidence: 91%

“…QCD sum rule approach QCD sum rules have been widely employed in the analysis of the ρ-meson mass at finite nuclear density [13,14,15,16,17,18,19]. Universally dropping masses were supported by early studies based on this approach [13,16,17].…”

Section: A Brown-rho Scaling and Dropping ρ-Mass In Nuclear Mediummentioning

confidence: 99%

Mass and width of the ρ-meson in a nuclear medium from Brown-Rho scaling and QCD sum rules

2006

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We explore the range of values of the in-medium width of a ρ-meson at rest which is compatibale with the QCD sum rule approach in a nuclear medium assuming vector meson dominance and a Brown-Rho scaling law of the ρ-meson mass with the chiral condensate. The lower and upper bounds for the in-medium width are found to be strongly increasing with the decreasing mass of the ρ-meson (increasing nuclear density). We also study the bounds for the in-medium width in models not satisfying the Brown-Rho scaling law. It is shown that the in-medium width depends on how rapidly the mass decreases in comparison to the change of the quark condensate. The bounds for the in-medium width increase with density only if the relative change of the quark condensate is stronger than the relative decrease in mass. This is important for experimental tests of the Brown-Rho scaling paradigm and other dropping ρ-mass scenarios.

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QCD sum rules, scattering length, and vector mesons in the nuclear medium

Cited by 88 publications

References 24 publications

QCD sum rules at finite density in the large- limit: the coupling of the ρ-nucleon system to the

QCD sum rules at finite density in the large- limit: the coupling of the ρ-nucleon system to the

ρ−ωmixing in asymmetric nuclear matter via a QCD sum rule approach

Mass and width of the ρ-meson in a nuclear medium from Brown-Rho scaling and QCD sum rules

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