Photon emission from quark-gluon plasma: complete leading order results

Arnold, Peter; Moore, Guy D.; Yaffe, Laurence G.

doi:10.1088/1126-6708/2001/12/009

Cited by 485 publications

(761 citation statements)

References 32 publications

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“…When τ −1 f λ q ≫ 1 the photons decohere early from the parent quark and our result reduces to incoherent emission from individual scattering centers. Our result differs from previous findings [7,9] in several important ways: first, it treats the case of finite L/λ q ∼ few, relevant to heavy ion physics. Second, we find that the most significant contribution to the LPM effect for photons comes from the interference of the medium-induced photon radiation with the hard emission from the large Q 2 scattering of the parent quark.…”

Section: Differential Photon Bremsstrahlung Spectrum To All Ordecontrasting

confidence: 99%

A systematic study of direct photon production in heavy ion collisions

Vitev

Zhang

2008

Physics Letters B

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A theoretical derivation of photon bremsstrahlung, induced by the interactions of an energetic quark in a hot and dense quark-gluon plasma, is given in the framework of the reaction operator approach. For the physically relevant case of hard jet production, followed by few in-medium interactions, we find that the Landau-Pomeranchuk-Migdal suppression of the bremsstrahlung photon intensity is much stronger than in the previously discussed limit of on-shell quarks and a large number of soft scatterings. This result is incorporated in the first systematic study of direct photon production in minimum bias d+Cu and d+Au and central Cu+Cu and Au+Au heavy ion collisions at the Relativistic Heavy Ion Collider at center of mass energies √ s = 62.4 GeV and 200 GeV. We find that the contribution of the photons created via final-state interactions is limited to 35% for 2 GeV< pT < 5 GeV and at high transverse momenta the modification of the direct photon cross section is dominated by initial-state cold nuclear matter effects.

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Section: Differential Photon Bremsstrahlung Spectrum To All Ordecontrasting

confidence: 99%

A systematic study of direct photon production in heavy ion collisions

Vitev

Zhang

2008

Physics Letters B

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“…This mechanism is quite similar to that for the photon radiation from hard quarks [16] and to the induced gluon radiation from fast partons [41]. The data analyses based on the standard formulas of [39] calculated for the fixed QCD coupling constant awaken a lively interest in such calculations with the running coupling constant (and changing the thermal quark mass). It looks like a quite relevant task, at least for the energy range covered by RHIC and LHC where the QGP, as we know, is strongly coupled.…”

Section: Prethermal and Thermal Photon Spectramentioning

confidence: 53%

“…Moreover, in our present calculations we are handling iHKM with the same set of parameters as used for describing almost all bulk hadron observables in the past (see [3]). Thus, in estimating the thermal emission from the QGP phase we draw attention to the expression of [39] with the number of quarks n f = 3 as for the LHC data…”

Section: Prethermal and Thermal Photon Spectramentioning

confidence: 99%

Direct-photon spectrum and elliptic flow produced from Pb+Pb collisions at sNN=2.76 TeV at the CERN Large Hadron Collider within an integrated hydrokinetic model

2018

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The photon transverse momentum spectrum and its anisotropy from Pb+Pb collisions at the CERN Large Hadron Collider energy √ s NN = 2.76 TeV are investigated within the integrated hydrokinetic model (iHKM). Photon production is accumulated from the different processes at the various stages of relativistic heavy ion collisions: from the primary hard photons of very early stage of parton collisions to the thermal photons from equilibrated quark-gluon and hadron gas stages. Along the way a hadronic medium evolution is treated in two distinct, in a sense opposite, approaches: chemically equilibrated and chemically frozen system expansion. Studying the centrality dependence of the results obtained allows us to conclude that a relatively strong transverse momentum anisotropy of thermal radiation is suppressed by prompt photon emission which is an isotropic. We find out that this effect is getting stronger as centrality increases because of the simultaneous increase in the relative contribution of prompt photons in the soft part of the spectra. The substantial results obtained in iHKM with nonzero viscosity (η/s = 0.08) for photon spectra and v 2 coefficients are mostly within the error bars of experimental data, but there is some systematic underestimation of both observables for the near central events. We claim that a situation could be significantly improved if an additional photon radiation that accompanies the presence of a deconfined environment is included. Since a matter of a space-time layer where hadronization takes place is actively involved in anisotropic transverse flow, both positive contributions to the spectra and v 2 are considerable, albeit such an argument needs further research and elaboration.

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“…(3.21) is well known and can be expressed in terms of a path integral in the transverse plane, leading to 22) where U (x + , y + ; [r]) is defined in eq. (3.14) and the boundary conditions are r(y + ) = y and r(x + ) = x.…”

Section: Jhep01(2013)031mentioning

confidence: 99%

Jet coherence in QCD media: the antenna radiation spectrum

Mehtar-Tani

Tywoniuk

2013

J. High Energ. Phys.

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Abstract:We study the radiation of a highly energetic partonic antenna in a colored state traversing a dense QCD medium. Resumming multiple scatterings of all involved constituents with the medium we derive the general gluon spectrum which encompasses both longitudinal color coherence between scattering centers in the medium, responsible for the well known Landau-Pomeranchuk-Migdal (LPM) effect, and transverse color coherence between partons inside a jet, leading, in vacuum, to angular ordering of the parton shower. We discuss shortly the onset of transverse decoherence which is reached in opaque media. In this regime, the spectrum consists of independent radiation off the antenna constituents.

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Photon emission from quark-gluon plasma: complete leading order results

Cited by 485 publications

References 32 publications

A systematic study of direct photon production in heavy ion collisions

A systematic study of direct photon production in heavy ion collisions

Direct-photon spectrum and elliptic flow produced from Pb+Pb collisions at sNN=2.76 TeV at the CERN Large Hadron Collider within an integrated hydrokinetic model

Jet coherence in QCD media: the antenna radiation spectrum

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