Hadronic production of thermal photons

Turbide, Simon; Rapp, Ralf; Gale, Charles

doi:10.1103/physrevc.69.014903

Cited by 363 publications

(642 citation statements)

References 76 publications

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“…7. Partial contributions are calculated in [14,20] and the solid curve is the sum of all subprocesses; it describes the data very well. Remarkably, this calculation uses an expanding fireball with τ 0 = 0.33fm/c and T i = 370MeV, double the formation time and only 2/3 of the temperature conjectured in [21] and applied on Fig.…”

Section: Internal Conversion Photons In Au+au Collisionsmentioning

confidence: 99%

“…6 that the overall yields of high-p T photons (integrated over azimuth) scale Predictions for direct photon spectra combining pQCD initial, jet-plasma interactions [20] as well as thermal radiation [14], compared to preliminary PHENIX data. The lines labeled "Th-Th" and "HG" correspond to the usual thermal radiation from QGP and hadron gas, respectively.…”

Section: Azimuthal Asymmetries In Direct Photon Productionmentioning

confidence: 99%

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Electromagnetic Probes in PHENIX

David

2007

Nuclear Physics A

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Electromagnetic probes are arguably the most universal tools to study the different physics processes in high energy hadron and heavy ion collisions. In this paper we summarize recent measurements of real and virtual direct photons at central rapidity by the PHENIX experiment at RHIC in p+p, d+Au and Au+Au collisions. We also discuss the impact of the results and the constraints they put on theoretical models. At the end we report on the immediate as well as on the mid-term future of photon measurements in PHENIX.

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Section: Internal Conversion Photons In Au+au Collisionsmentioning

confidence: 99%

Section: Azimuthal Asymmetries In Direct Photon Productionmentioning

confidence: 99%

Electromagnetic Probes in PHENIX

David

2007

Nuclear Physics A

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“…Ref. [13] for a recent analysis in hot hadronic matter). We will comment on the effects of kaons and other strangeness-bearing mesons in the summary.…”

Section: Introductionmentioning

confidence: 99%

Photon emission from dense quark matter

2004

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Thermal emission rates and mean free paths of photons in a color-flavor locked (CFL) phase of quark matter at high densities and moderate temperatures are evaluated. Our calculations are based on a low-energy effective theory for CFL matter describing Goldstone boson excitations and their electromagnetic as well as strong interactions. Inmedium coupling strengths of vector mesons are estimated to be smaller than in vacuum. As a consequence of in-medium modified pion dispersion relations, novel processes such as π + π − → γ and γ → π + π − become possible. The total photon emissivity is found to be very large, exceeding contributions from thermal e + e − annihilation above temperatures of about 5 MeV. At the same time, the corresponding mean free paths become very small. Our results imply that the photon flux from the surface of a (hypothetical) CFL star in its early hot stages saturates the black-body limit. Schematic estimates for the early thermal evolution of the star are also presented.

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“…[38][39][40][41]. The contributions from the reactions involving strange mesons like πK * → Kγ, πK → K * γ, ρK → Kγ and KK * → Kγ, have been pointed out in [42] Contributions from other decays, such as K * (892) → K γ, φ → η γ, b 1 (1235) → π γ, a 2 (1320) → π γ and K 1 (1270) → π γ have been found to be small [43] for p T > 1 GeV. We consider all the processes for our calculation.…”

mentioning

confidence: 99%

“…All the isospin combinations for the above reactions and decays have properly been taken into account. The effects of hadronic form factors(dipole) [42] have been incorporated.…”

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confidence: 99%

Electromagnetic signals from Au + Au collisions at RHIC energy, sNN=200 GeV and Pb + Pb collisions at LHC energy,
Nayak
¹
,
Sinha
²

2013
Physics Letters B
5
0
2
0
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We analyse the recently available experimental data on direct photon productions from Au+Au collisions at √ sNN =200 GeV RHIC and from Pb+Pb collisions at √ sNN =2.76 TeV LHC energies. The transverse momentum (pT ) distributions have been evaluated with the assumption of an initial quark gluon plasma phase at temperatures Ti=404 and 546 MeV with initial thermalisation times τi=0.2 and 0.1 fm/c respectively for RHIC and LHC energies. The theoretical evalutions agree reasonably well with the experimental observations. The thermal window for the LHC energy is justified through the ratio of the pT spectra of thermal photons to dileptons.PACS numbers: 25.75.Dw,24.85.+p It is by now conventional wisdom, that collisions between two nuclei at RHIC as well as LHC energies will lead to the formation of quark gluon plasma (QGP). Although the exact nature of QGPhadron phase transition is still plagued by uncertainties, but there are several evidences that QGP is formed [1][2][3][4] at RHIC energies. It has long been recognised that promising signals of QGP are photons and dileptons [5][6][7][8][9]. The very nature of electromagnetic interactions ensures that the thermometric signals (γ, µ + µ − , e + e − ) escape the QGP medium without any significant interaction, thus retaining the pristine information of QGP immediately after its formation. It has been pointed out by one of the authors and his collaborators, consistently for a long time [8][9][10][11][12][13][14], that the photons emanating from thermal medium show up in the p T window of 1.5 ≤ p T (GeV ) ≤ 3.5. It has also been pointed out [15,16] during the early days of QGP physics and now, that the ratio γ/µ + µ − eliminates some of the uncertainties associated with the input parameters used in the model.The concept of ratio has been revisited again in ref [17,18] where the sensitivities of the of the initial parameters have been studied extensively. The formation of a thermal medium is manifested by the flattering of the ratio beyond certain p T . Now that the direct photon data has come out of LHC we tend to analyse the data and test the above prediction at √ s N N =2.76 TeV. It is quite remarkable that the original theoretical prediction [15][16][17][18] turns out to be valid also at LHC energies with added advantage that the very high energy of LHC turns the invariant mass M , of dileptons less relevant compare to (say) at RHIC energies.It should also be noted that there is already a tantalising hint of QGP formation even at SPS energy [19,20]. In the following work we present our findings of this interesting phenomenon. Thus over a wide range of energies going through orders of magnitude, it is quite exciting to note that p T window for thermal photons and dileptons remains the same as predicted earlier, only the range of window increases almost upto 4 GeV or more at LHC energy.In this present work we have evaluated the direct photon productions from (i) Au+Au collisions at √ s N N =200 GeV for 0-5% centrality and (ii) Pb+Pb collisions at √ s N N =2.76 TeV for...

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Hadronic production of thermal photons

Cited by 363 publications

References 76 publications

Electromagnetic Probes in PHENIX

Electromagnetic Probes in PHENIX

Photon emission from dense quark matter

Electromagnetic signals from Au + Au collisions at RHIC energy, sNN=200 GeV and Pb + Pb collisions at LHC energy,
Nayak
¹
,
Sinha
²

2013
Physics Letters B
5
0
2
0
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Hadronic production of thermal photons

Cited by 363 publications

References 76 publications

Electromagnetic Probes in PHENIX

Electromagnetic Probes in PHENIX

Photon emission from dense quark matter

Electromagnetic signals from Au + Au collisions at RHIC energy, sNN=200 GeV and Pb + Pb collisions at LHC energy, Nayak1, Sinha2 2013Physics Letters B5020View full textAdd to dashboardCite

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Electromagnetic signals from Au + Au collisions at RHIC energy, sNN=200 GeV and Pb + Pb collisions at LHC energy,
Nayak
¹
,
Sinha
²

2013
Physics Letters B
5
0
2
0
View full text Add to dashboard Cite