Virtual-photon bremsstrahlung in a quark-gluon plasma

Cleymans, J.; Головизнин, В. В.; Redlich, K.

doi:10.1103/physrevd.47.989

Cited by 34 publications

(60 citation statements)

References 17 publications

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“…Moreover, our considerations show that the condition Γ ≪ǭ is not at all sufficient. Rather one has to demand that also ω ≫ Γ in the QPA, since finally energy differences of order ω appear 14 . In particular, the remaining series of QPA-diagrams is no longer convergent unless ω > Γ, since arbitrary powers in Γ/ω appear, and there is no hope to ever recover a reliable result by a finite number of QPA-diagrams for the production of soft quanta!…”

Section: Decomposition Of Closed Diagrams Into Feynman Amplitudes In mentioning

confidence: 99%

“…Its propagation in the equilibrated matter is also governed by the Fokker Planck equation (14). By a Gaussian ansatz for the Fourier transform of this fluctuation …”

Section: Diffusion Processmentioning

confidence: 99%

“…This however is only true if < v m v m+n > m = 0 for n = 0, an approximation recently used in refs. [14]. In the general case velocity correlations between successive scatterings exist, and there will be a difference between the microscopic mean collision rate Γ and the mesoscopic relaxation rate Γ x .…”

Section: Microscopic Langevin Processmentioning

confidence: 99%

“…see refs. [14,5], where the role of the matter is reduced to infinitely massive scatterers. In reality all the particles in dense matter which couple to the radiated field should be treated on equal footing.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Classical and Quantum Many-Body Description of Bremsstrahlung in Dense Matter

Knoll¹,

Voskresensky²

1996

Annals of Physics

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Some considerations about the importance of coherence effects for bremsstrahlung processes in non-equilibrium dense matter (Landau -Pomeranchuk -Migdal -effect) are presented. They are of particular relevance for the application to photonand di-lepton production from high energy nuclear collisions, to gluon radiation in QCD transport, or parton kinetics and to neutrino and axion radiation from supernova explosion and from hot neutron stars. The soft behavior of the bremsstrahlung from a source described by classical transport models is discussed and pocket correction formulas for the in-matter radiation cross sections are suggested in terms of standard transport coefficients. The radiation rates are also discussed within a non-equilibrium quantum field theory (Schwinger -Kadanoff -Baym -Keldysh) formulation. A classification of diagrams and corresponding resummation in physically meaningful terms is proposed, which considers the finite damping width of all source particles in matter. This way each diagram in this expansion is already free from the infra-red divergences. Both, the correct quasi-particle and quasi-classical limits are recovered from this subset of graphs. Explicit results are given for dense matter in thermal equilibrium. The diagrammatic description may suggest a formulation of a transport theory that includes the propagation of off-shell particles in non-equilibrium dense matter.

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Section: Decomposition Of Closed Diagrams Into Feynman Amplitudes In mentioning

confidence: 99%

“…Its propagation in the equilibrated matter is also governed by the Fokker Planck equation (14). By a Gaussian ansatz for the Fourier transform of this fluctuation …”

Section: Diffusion Processmentioning

confidence: 99%

Section: Microscopic Langevin Processmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Classical and Quantum Many-Body Description of Bremsstrahlung in Dense Matter

Knoll¹,

Voskresensky²

1996

Annals of Physics

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“…In the hadronic gas at temperature T the thermal photon rates were analyzed in [30] where all contributions originating from the two loop approximation of the real photon self energy using model with π − ρ interactions were calculated. The dominant contribution to the photon rate was found to be Compton πρ → πγ, decay ρ → ππγ and the annihilation ππ → ργ, processes.…”

Section: Thermal Photon Yieldmentioning

confidence: 99%

Thermal particle and photon production in Pb+Pb collisions with transverse flow

1997

Self Cite

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Particle and photon production is analyzed in the presence of transverse flow using two approximations to describe the properties of the hadronic medium, one containing only π, ρ, ω, and η mesons (simplified equation of state) and the other containing hadrons and resonances from the particle data table. Both are considered with and without initial quark gluon plasma formation. In each case the initial temperature is fixed by requiring dN ch /dy ∼ 550 in the final state.It is shown that most observables are very sensitive to the equation of state. This is particularly evident when comparing the results of the simplified equation of state in the scenarios with and without phase transition. The hadronic gas scenario leads to a substantially higher rate for the pT -distribution of all particles.In the complete equation of state with several hundreds of hadronic resonances, the difference between the scenarios with and without phase transition is rather modest. Both photon and particle spectra, in a wide pT range, show very similar behavior. It is therefore concluded that from the pT spectra it will be hard to disentangle quark gluon plasma formation in the initial state. It is to be stressed however, that there are conceptual difficulties in applying a pure hadronic gas equation of state at SPS-energies. The phase transition scenario with a quark gluon plasma present in the initial state seems to be the more natural one.

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Chiral Symmetry Restoration and Dileptons in Relativistic Heavy-Ion Collisions

Rapp

Wambach

2002

Advances in Nuclear Physics

548

258

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The current theoretical status in the analysis and interpretation of low-mass dilepton measurements in (ultra-) relativistic heavy-ion experiments is reviewed. Special emphasis is put on potential signals of (partial) restoration of dynamically broken chiral symmetry in a hot and dense hadronic medium. It follows from chiral symmetry alone that parity partners of hadronic correlation functions must become identical when the symmetry is restored. The assessment of medium effects in the vector channel, which governs the dilepton production, thus necessitates a simultaneous treatment of the vector and axialvector degrees of freedom. While significant progress in this respect has been made some open questions remain in establishing a rigorous link in the mass region below 1 GeV. From the present calculations a suggestive 'quark-hadron duality' emerges near the phase boundary. It implies substantial medium effects in the dilepton signal from the hadronic phase which smoothly matches a perturbative description within the plasma phase.

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Virtual-photon bremsstrahlung in a quark-gluon plasma

Cited by 34 publications

References 17 publications

Classical and Quantum Many-Body Description of Bremsstrahlung in Dense Matter

Classical and Quantum Many-Body Description of Bremsstrahlung in Dense Matter

Thermal particle and photon production in Pb+Pb collisions with transverse flow

Chiral Symmetry Restoration and Dileptons in Relativistic Heavy-Ion Collisions

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