Direct photon production in Pb–Pb collisions at √sNN=2.76 TeV
(2016) In Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics 754. p.235-248- Abstract
- Direct photon production at mid-rapidity in Pb–Pb collisions at sNN=2.76 TeV was studied in the transverse momentum range 0.9<pT<14 GeV/c. Photons were detected with the highly segmented electromagnetic calorimeter PHOS and via conversions in the ALICE detector material with the e+e− pair reconstructed in the central tracking system. The results of the two methods were combined and direct photon spectra were measured for the 0–20%, 20–40%, and 40–80% centrality classes. For all three classes, agreement was found with perturbative QCD calculations for pT≳5 GeV/c. Direct photon spectra down to pT≈1 GeV/c could be extracted for the 20–40% and 0–20% centrality classes. The significance of the direct photon signal for 0.9<pT<2.1... (More)
- Direct photon production at mid-rapidity in Pb–Pb collisions at sNN=2.76 TeV was studied in the transverse momentum range 0.9<pT<14 GeV/c. Photons were detected with the highly segmented electromagnetic calorimeter PHOS and via conversions in the ALICE detector material with the e+e− pair reconstructed in the central tracking system. The results of the two methods were combined and direct photon spectra were measured for the 0–20%, 20–40%, and 40–80% centrality classes. For all three classes, agreement was found with perturbative QCD calculations for pT≳5 GeV/c. Direct photon spectra down to pT≈1 GeV/c could be extracted for the 20–40% and 0–20% centrality classes. The significance of the direct photon signal for 0.9<pT<2.1 GeV/c is 2.6σ for the 0–20% class. The spectrum in this pT range and centrality class can be described by an exponential with an inverse slope parameter of (297±12stat±41syst) MeV. State-of-the-art models for photon production in heavy-ion collisions agree with the data within uncertainties.
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https://lup.lub.lu.se/record/394773a6-cef9-499a-96ce-269c50b07adc
- author
- J., Adam ; Christiansen, P. LU ; Ljunggren, H. ; Oskarsson, A. LU ; Richert, T. LU ; Silvermyr, D. LU ; Søgaard, C. LU ; Stenlund, E. LU ; Vislavicius, V. LU and M., Zyzak
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- 2016
- type
- Contribution to journal
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- published
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- in
- Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
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- 754
- pages
- 14 pages
- publisher
- Elsevier
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- scopus:85040813298
- ISSN
- 0370-2693
- DOI
- 10.1016/j.physletb.2016.01.020
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- English
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- yes
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- 394773a6-cef9-499a-96ce-269c50b07adc
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- 2022-04-04 14:48:06
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- 2023-05-10 15:22:32
@article{394773a6-cef9-499a-96ce-269c50b07adc, abstract = {{Direct photon production at mid-rapidity in Pb–Pb collisions at sNN=2.76 TeV was studied in the transverse momentum range 0.9<pT<14 GeV/c. Photons were detected with the highly segmented electromagnetic calorimeter PHOS and via conversions in the ALICE detector material with the e+e− pair reconstructed in the central tracking system. The results of the two methods were combined and direct photon spectra were measured for the 0–20%, 20–40%, and 40–80% centrality classes. For all three classes, agreement was found with perturbative QCD calculations for pT≳5 GeV/c. Direct photon spectra down to pT≈1 GeV/c could be extracted for the 20–40% and 0–20% centrality classes. The significance of the direct photon signal for 0.9<pT<2.1 GeV/c is 2.6σ for the 0–20% class. The spectrum in this pT range and centrality class can be described by an exponential with an inverse slope parameter of (297±12stat±41syst) MeV. State-of-the-art models for photon production in heavy-ion collisions agree with the data within uncertainties. <br/>}}, author = {{J., Adam and Christiansen, P. and Ljunggren, H. and Oskarsson, A. and Richert, T. and Silvermyr, D. and Søgaard, C. and Stenlund, E. and Vislavicius, V. and M., Zyzak}}, issn = {{0370-2693}}, language = {{eng}}, pages = {{235--248}}, publisher = {{Elsevier}}, series = {{Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics}}, title = {{Direct photon production in Pb–Pb collisions at √sNN=2.76 TeV}}, url = {{http://dx.doi.org/10.1016/j.physletb.2016.01.020}}, doi = {{10.1016/j.physletb.2016.01.020}}, volume = {{754}}, year = {{2016}}, }