Direct-Photon Spectra and Anisotropic Flow in Heavy Ion Collisions from Holography
The thermal-photon emission from strongly coupled gauge theories at finite temperature is calculated by using holographic models for QCD in the Veneziano limit (V-QCD). These emission rates are then embedded in hydrodynamic simulations combined with prompt photons from hard scattering and the therma...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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EDP Sciences
2017-01-01
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| Series: | EPJ Web of Conferences |
| Online Access: | https://doi.org/10.1051/epjconf/201713707029 |
| _version_ | 1818597331947225088 |
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| author | Iatrakis Ioannis Kiritsis Elias Shen Chun Yang Di-Lun |
| author_facet | Iatrakis Ioannis Kiritsis Elias Shen Chun Yang Di-Lun |
| author_sort | Iatrakis Ioannis |
| collection | DOAJ |
| description | The thermal-photon emission from strongly coupled gauge theories at finite temperature is calculated by using holographic models for QCD in the Veneziano limit (V-QCD). These emission rates are then embedded in hydrodynamic simulations combined with prompt photons from hard scattering and the thermal photons from hadron gas to analyze the spectra and anisotropic flow of direct photons at RHIC and LHC. The results from different sources responsible for the thermal photons in the quark gluon plasma (QGP) including the weakly coupled QGP (wQGP) from perturbative calculations, strongly coupled N = 4 super Yang-Mills (SYM) plasma (as a benchmark for reference), and Gubser’s phenomenological model mimicking the strongly coupled QGP (sQGP) are then compared. It is found that the direct-photon spectra are enhanced in the strongly coupled scenario compared with the ones in the wQGP, especially at intermediate and high momenta, which improve the agreements with data. Moreover, by using IP-glassma initial states, both the elliptic flow and triangular flow of direct photons are amplified at high momenta (pT > 2.5 GeV) for V-QCD, while they are suppressed at low momenta compared to wQGP. The distinct results in holography stem from the blue-shift of emission rates in strong coupling. In addition, the spectra and flow in small collision systems were evaluated for future comparisons. It is found that thermal photons from the deconfined phase are substantial to reconcile the spectra and flow at high momenta. |
| first_indexed | 2024-12-16T11:46:07Z |
| format | Article |
| id | doaj.art-b2900a1dc5fa49918d3ee5793a454249 |
| institution | Directory Open Access Journal |
| issn | 2100-014X |
| language | English |
| last_indexed | 2024-12-16T11:46:07Z |
| publishDate | 2017-01-01 |
| publisher | EDP Sciences |
| record_format | Article |
| series | EPJ Web of Conferences |
| spelling | doaj.art-b2900a1dc5fa49918d3ee5793a4542492022-12-21T22:32:50ZengEDP SciencesEPJ Web of Conferences2100-014X2017-01-011370702910.1051/epjconf/201713707029epjconf_conf2017_07029Direct-Photon Spectra and Anisotropic Flow in Heavy Ion Collisions from HolographyIatrakis Ioannis0Kiritsis EliasShen Chun1Yang Di-Lun2Institute for Theoretical Physics and Center for Extreme Matter and Emergent Phenomena, Utrecht UniversityDepartment of Physics, McGill UniversityTheoretical Research Division, Nishina Center, RIKENThe thermal-photon emission from strongly coupled gauge theories at finite temperature is calculated by using holographic models for QCD in the Veneziano limit (V-QCD). These emission rates are then embedded in hydrodynamic simulations combined with prompt photons from hard scattering and the thermal photons from hadron gas to analyze the spectra and anisotropic flow of direct photons at RHIC and LHC. The results from different sources responsible for the thermal photons in the quark gluon plasma (QGP) including the weakly coupled QGP (wQGP) from perturbative calculations, strongly coupled N = 4 super Yang-Mills (SYM) plasma (as a benchmark for reference), and Gubser’s phenomenological model mimicking the strongly coupled QGP (sQGP) are then compared. It is found that the direct-photon spectra are enhanced in the strongly coupled scenario compared with the ones in the wQGP, especially at intermediate and high momenta, which improve the agreements with data. Moreover, by using IP-glassma initial states, both the elliptic flow and triangular flow of direct photons are amplified at high momenta (pT > 2.5 GeV) for V-QCD, while they are suppressed at low momenta compared to wQGP. The distinct results in holography stem from the blue-shift of emission rates in strong coupling. In addition, the spectra and flow in small collision systems were evaluated for future comparisons. It is found that thermal photons from the deconfined phase are substantial to reconcile the spectra and flow at high momenta.https://doi.org/10.1051/epjconf/201713707029 |
| spellingShingle | Iatrakis Ioannis Kiritsis Elias Shen Chun Yang Di-Lun Direct-Photon Spectra and Anisotropic Flow in Heavy Ion Collisions from Holography EPJ Web of Conferences |
| title | Direct-Photon Spectra and Anisotropic Flow in Heavy Ion Collisions from Holography |
| title_full | Direct-Photon Spectra and Anisotropic Flow in Heavy Ion Collisions from Holography |
| title_fullStr | Direct-Photon Spectra and Anisotropic Flow in Heavy Ion Collisions from Holography |
| title_full_unstemmed | Direct-Photon Spectra and Anisotropic Flow in Heavy Ion Collisions from Holography |
| title_short | Direct-Photon Spectra and Anisotropic Flow in Heavy Ion Collisions from Holography |
| title_sort | direct photon spectra and anisotropic flow in heavy ion collisions from holography |
| url | https://doi.org/10.1051/epjconf/201713707029 |
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