Prompt photon production and photon-jet correlations at the LHC

  • Michael Klasen
  • Christian Klein-Bösing
  • Hendrik Poppenborg
Open Access
Regular Article - Theoretical Physics


Next-to-leading order predictions matched to parton showers are compared with recent ATLAS data on isolated photon production and CMS data on associated photon and jet production in pp and pPb collisions at different centre-of-mass energies of the LHC. We find good agreement and, as expected, considerably reduced scale uncertainties compared to previous theoretical calculations. Predictions are made for the ratio of inclusive photons over decay photons Rγ , an important quantity to evaluate the significance of additional photon sources, e.g. thermal radiation from a Quark-Gluon-Plasma, and for distributions in the parton momentum fraction in lead ions x Pb obs , that could be determined by ALICE, ATLAS, CMS and LHCb in ongoing analyses of photon+jet production in pPb collisions at \( \sqrt{s_{N\ N}} = 5.02 \) TeV. These data should have an important impact on the determination of nuclear effects such as shadowing at low x.


Heavy Ion Phenomenology NLO Computations 


Open Access

This article is distributed under the terms of the Creative Commons Attribution License (CC-BY 4.0), which permits any use, distribution and reproduction in any medium, provided the original author(s) and source are credited.


  1. [1]
    S. Albino, M. Klasen and S. Soldner-Rembold, Strong coupling constant from the photon structure function, Phys. Rev. Lett. 89 (2002) 122004 [hep-ph/0205069] [INSPIRE].
  2. [2]
    M. Klasen, Theory of hard photoproduction, Rev. Mod. Phys. 74 (2002) 1221 [hep-ph/0206169] [INSPIRE].
  3. [3]
    T. Stavreva et al., Probing gluon and heavy-quark nuclear PDFs with γ + Q production in pA collisions, JHEP 01 (2011) 152 [arXiv:1012.1178] [INSPIRE].ADSCrossRefMATHGoogle Scholar
  4. [4]
    M. Brandt, M. Klasen and F. König, Nuclear parton density modifications from low-mass lepton pair production at the LHC, Nucl. Phys. A 927 (2014) 78 [arXiv:1401.6817] [INSPIRE].
  5. [5]
    M. Klasen, K. Kovarik and J. Potthoff, Nuclear parton density functions from jet production in DIS at an EIC, Phys. Rev. D 95 (2017) 094013 [arXiv:1703.02864] [INSPIRE].
  6. [6]
    P.B. Arnold, G.D. Moore and L.G. Yaffe, Photon emission from quark gluon plasma: Complete leading order results, JHEP 12 (2001) 009 [hep-ph/0111107] [INSPIRE].
  7. [7]
    M. Klasen, C. Klein-Bösing, F. König and J.P. Wessels, How robust is a thermal photon interpretation of the ALICE low-p T data?, JHEP 10 (2013) 119 [arXiv:1307.7034] [INSPIRE].
  8. [8]
    X.-N. Wang, Z. Huang and I. Sarcevic, Jet quenching in the opposite direction of a tagged photon in high-energy heavy ion collisions, Phys. Rev. Lett. 77 (1996) 231 [hep-ph/9605213] [INSPIRE].
  9. [9]
    T. Sjöstrand, S. Mrenna and P.Z. Skands, A brief introduction to PYTHIA 8.1, Comput. Phys. Commun. 178 (2008) 852 [arXiv:0710.3820] [INSPIRE].
  10. [10]
    ALICE collaboration, Inclusive photon production at forward rapidities in proton-proton collisions at \( \sqrt{s} = 0.9,2.76 \) and 7 TeV, Eur. Phys. J. C 75 (2015) 146 [arXiv:1411.4981] [INSPIRE].
  11. [11]
    ALICE collaboration, Direct photon production in Pb-Pb collisions at \( \sqrt{s_{\mathrm{NN}}}=2.76 \) TeV, Phys. Lett. B 754 (2016) 235 [arXiv:1509.07324] [INSPIRE].
  12. [12]
    ATLAS collaboration, Measurement of the cross section for inclusive isolated-photon production in pp collisions at \( \sqrt{s}=13 \) TeV using the ATLAS detector, Phys. Lett. B 770 (2017)473 [arXiv:1701.06882] [INSPIRE].
  13. [13]
    ATLAS collaboration, Centrality, rapidity and transverse momentum dependence of isolated prompt photon production in lead-lead collisions at \( \sqrt{s_{\mathrm{NN}}}=2.76 \) TeV measured with the ATLAS detector, Phys. Rev. C 93 (2016) 034914 [arXiv:1506.08552] [INSPIRE].
  14. [14]
    CMS collaboration, Study of isolated photon jet correlation in PbPb and pp collisions at 2.76 TeV and pPb collisions at 5.02 TeV, CMS-PAS-HIN-13-006 (2013).
  15. [15]
    LHCb collaboration, First experimental study of photon polarization in radiative B s0 decays, Phys. Rev. Lett. 118 (2017) 021801 [arXiv:1609.02032] [INSPIRE].
  16. [16]
    S. Catani, M. Fontannaz, J.P. Guillet and E. Pilon, Cross-section of isolated prompt photons in hadron hadron collisions, JHEP 05 (2002) 028 [hep-ph/0204023] [INSPIRE].
  17. [17]
    P. Aurenche, M. Fontannaz, J.-P. Guillet, E. Pilon and M. Werlen, A new critical study of photon production in hadronic collisions, Phys. Rev. D 73 (2006) 094007 [hep-ph/0602133] [INSPIRE].
  18. [18]
    CDF collaboration, T. Aaltonen et al., Measurement of the inclusive isolated prompt photon cross section in \( p\overline{p} \) collisions at \( \sqrt{s}=1.96 \) TeV using the CDF detector, Phys. Rev. D 80 (2009)111106 [arXiv:0910.3623] [INSPIRE].
  19. [19]
    D0 collaboration, V.M. Abazov et al., Measurement of the differential cross sections for isolated direct photon pair production in \( p\overline{p} \) collisions at \( \sqrt{s}=1.96 \) TeV, Phys. Lett. B 725 (2013)6 [arXiv:1301.4536] [INSPIRE].
  20. [20]
    D0 collaboration, V.M. Abazov et al., Measurement of the differential cross section of photon plus jet production in \( p\overline{p} \) collisions at \( \sqrt{s}=1.96 \) TeV, Phys. Rev. D 88 (2013) 072008 [arXiv:1308.2708] [INSPIRE].
  21. [21]
    CDF collaboration, T. Aaltonen et al., Measurement of the cross section for direct-photon production in association with a heavy quark in \( p\overline{p} \) collisions at \( \sqrt{s}=1.96 \) TeV, Phys. Rev. Lett. 111 (2013) 042003 [arXiv:1303.6136] [INSPIRE].
  22. [22]
    D0 collaboration, V.M. Abazov et al., Measurement of the differential photon + c-jet cross section and the ratio of differential photon+ c and photon+ b cross sections in proton-antiproton collisions at \( \sqrt{s}=1.96 \) TeV, Phys. Lett. B 719 (2013) 354 [arXiv:1210.5033] [INSPIRE].
  23. [23]
    L. Bourhis, M. Fontannaz and J.P. Guillet, Quarks and gluon fragmentation functions into photons, Eur. Phys. J. C 2 (1998) 529 [hep-ph/9704447] [INSPIRE].
  24. [24]
    M. Klasen and F. König, New information on photon fragmentation functions, Eur. Phys. J. C 74 (2014) 3009 [arXiv:1403.2290] [INSPIRE].
  25. [25]
    T. Kaufmann, A. Mukherjee and W. Vogelsang, Access to photon fragmentation functions in hadronic jet production, Phys. Rev. D 93 (2016) 114021 [arXiv:1604.07175] [INSPIRE].
  26. [26]
    J.M. Campbell, R.K. Ellis, Y. Li and C. Williams, Predictions for diphoton production at the LHC through NNLO in QCD, JHEP 07 (2016) 148 [arXiv:1603.02663] [INSPIRE].ADSCrossRefGoogle Scholar
  27. [27]
    R. Boughezal et al., Color singlet production at NNLO in MCFM, Eur. Phys. J. C 77 (2017) 7 [arXiv:1605.08011] [INSPIRE].ADSCrossRefGoogle Scholar
  28. [28]
    J.M. Campbell, T. Neumann and C. Williams, Zγ production at NNLO including anomalous couplings, JHEP 11 (2017) 150 [arXiv:1708.02925] [INSPIRE].ADSCrossRefGoogle Scholar
  29. [29]
    J.M. Campbell, H.B. Hartanto and C. Williams, Next-to-leading order predictions for Zγ+jet and ZΓγ final states at the LHC, JHEP 11 (2012) 162 [arXiv:1208.0566] [INSPIRE].
  30. [30]
    S. Frixione, Z. Kunszt and A. Signer, Three jet cross-sections to next-to-leading order, Nucl. Phys. B 467 (1996) 399 [hep-ph/9512328] [INSPIRE].
  31. [31]
    S. Frixione, P. Nason and C. Oleari, Matching NLO QCD computations with Parton Shower simulations: the POWHEG method, JHEP 11 (2007) 070 [arXiv:0709.2092] [INSPIRE].ADSCrossRefGoogle Scholar
  32. [32]
    T. Jezo, M. Klasen and F. König, Prompt photon production and photon-hadron jet correlations with POWHEG, JHEP 11 (2016) 033 [arXiv:1610.02275] [INSPIRE].CrossRefGoogle Scholar
  33. [33]
    S. Hoeche, S. Schumann and F. Siegert, Hard photon production and matrix-element parton-shower merging, Phys. Rev. D 81 (2010) 034026 [arXiv:0912.3501] [INSPIRE].
  34. [34]
    T. Gehrmann, N. Greiner and G. Heinrich, Precise QCD predictions for the production of a photon pair in association with two jets, Phys. Rev. Lett. 111 (2013) 222002 [arXiv:1308.3660] [INSPIRE].ADSCrossRefGoogle Scholar
  35. [35]
    S. Badger, A. Guffanti and V. Yundin, Next-to-leading order QCD corrections to di-photon production in association with up to three jets at the Large Hadron Collider, JHEP 03 (2014) 122 [arXiv:1312.5927] [INSPIRE].ADSCrossRefGoogle Scholar
  36. [36]
    Z. Bern et al., Next-to-leading order γγ + 2-jet production at the LHC, Phys. Rev. D 90 (2014) 054004 [arXiv:1402.4127] [INSPIRE].
  37. [37]
    F. Siegert, A practical guide to event generation for prompt photon production with Sherpa, J. Phys. G 44 (2017) 044007 [arXiv:1611.07226] [INSPIRE].
  38. [38]
    T. Fritzsche et al., The implementation of the renormalized complex MSSM in FeynArts and FormCalc, Comput. Phys. Commun. 185 (2014) 1529 [arXiv:1309.1692] [INSPIRE].ADSCrossRefMATHGoogle Scholar
  39. [39]
    J. Alwall, M. Herquet, F. Maltoni, O. Mattelaer and T. Stelzer, MadGraph 5: going beyond, JHEP 06 (2011) 128 [arXiv:1106.0522] [INSPIRE].ADSCrossRefMATHGoogle Scholar
  40. [40]
    J.A.M. Vermaseren, New features of FORM, math-ph/0010025 [INSPIRE].
  41. [41]
    T. Hahn and M. Pérez-Victoria, Automatized one loop calculations in four-dimensions and D-dimensions, Comput. Phys. Commun. 118 (1999) 153 [hep-ph/9807565] [INSPIRE].
  42. [42]
    J. Alwall et al., The automated computation of tree-level and next-to-leading order differential cross sections and their matching to parton shower simulations, JHEP 07 (2014) 079 [arXiv:1405.0301] [INSPIRE].ADSCrossRefGoogle Scholar
  43. [43]
    S. Catani and M.H. Seymour, A general algorithm for calculating jet cross-sections in NLO QCD, Nucl. Phys. B 485 (1997) 291 [Erratum ibid. B 510 (1998) 503] [hep-ph/9605323] [INSPIRE].
  44. [44]
    K. Hasegawa, S. Moch and P. Uwer, AutoDipole: automated generation of dipole subtraction terms, Comput. Phys. Commun. 181 (2010) 1802 [arXiv:0911.4371] [INSPIRE].ADSMathSciNetCrossRefMATHGoogle Scholar
  45. [45]
    L. D’Errico and P. Richardson, Next-to-leading-order Monte Carlo simulation of diphoton production in hadronic collisions, JHEP 02 (2012) 130 [arXiv:1106.3939] [INSPIRE].ADSCrossRefGoogle Scholar
  46. [46]
    L. Barze et al., W γ production in hadronic collisions using the POWHEG+MiNLO method, JHEP 12 (2014) 039 [arXiv:1408.5766] [INSPIRE].ADSCrossRefGoogle Scholar
  47. [47]
    NNPDF collaboration, R.D. Ball et al., Parton distributions from high-precision collider data, Eur. Phys. J. C 77 (2017) 663 [arXiv:1706.00428] [INSPIRE].
  48. [48]
    NNPDF collaboration, R.D. Ball et al., Parton distributions with QED corrections, Nucl. Phys. B 877 (2013) 290 [arXiv:1308.0598] [INSPIRE].
  49. [49]
    P. Skands, S. Carrazza and J. Rojo, Tuning PYTHIA 8.1: the Monash 2013 Tune, Eur. Phys. J. C 74 (2014) 3024 [arXiv:1404.5630] [INSPIRE].
  50. [50]
    M. Cacciari and D. d’Enterria, private communication.Google Scholar
  51. [51]
    M. Cacciari, G.P. Salam and G. Soyez, The anti-k t jet clustering algorithm, JHEP 04 (2008) 063 [arXiv:0802.1189] [INSPIRE].ADSCrossRefMATHGoogle Scholar
  52. [52]
    X.-N. Wang and M. Gyulassy, HIJING: a Monte Carlo model for multiple jet production in p p, p A and A A collisions, Phys. Rev. D 44 (1991) 3501 [INSPIRE].
  53. [53]
    CMS collaboration, Study of isolated-photon + jet correlations in PbPb and pp collisions at \( \sqrt{s_{N\ N}}=5.02 \) TeV, CMS-PAS-HIN-16-002 (2016).
  54. [54]
    ATLAS collaboration, Measurement of the cross section for isolated-photon plus jet production in pp collisions at \( \sqrt{s}=13 \) TeV using the ATLAS detector, ATLAS-CONF-2017-059 (2017).
  55. [55]
    K. Kovarik et al., nCTEQ15 - Global analysis of nuclear parton distributions with uncertainties in the CTEQ framework, Phys. Rev. D 93 (2016) 085037 [arXiv:1509.00792] [INSPIRE].
  56. [56]
    D. Stump et al., Inclusive jet production, parton distributions and the search for new physics, JHEP 10 (2003) 046 [hep-ph/0303013] [INSPIRE].
  57. [57]
    K.J. Eskola, P. Paakkinen, H. Paukkunen and C.A. Salgado, EPPS16: nuclear parton distributions with LHC data, Eur. Phys. J. C 77 (2017) 163 [arXiv:1612.05741] [INSPIRE].
  58. [58]
    CMS Collaboration, Production of pairs of isolated photons in association with jets in pp collisions at \( \sqrt{s}=7 \) TeV, CMS-PAS-SMP-14-021 (2014).
  59. [59]
    ALICE collaboration, M. Germain, Direct photon measurements in pp and Pb-Pb collisions with the ALICE experiment, in the proceedings of the XXVI International Conference on Ultrarelativistic Heavy-Ion Collisions (Quark Matter 2017), February 5-11, Chicago, U.S.A. (2017), Nucl. Phys. A 967 (2017) 696.Google Scholar
  60. [60]
    ALICE collaboration, Measurement of charged jet production cross sections and nuclear modification in p-Pb collisions at \( \sqrt{s_{\mathrm{NN}}}=5.02 \) TeV, Phys. Lett. B 749 (2015) 68 [arXiv:1503.00681] [INSPIRE].
  61. [61]
    ALICE collaboration, Centrality dependence of charged jet production in p-Pb collisions at \( \sqrt{s_{\mathrm{NN}}}=5.02 \) TeV, Eur. Phys. J. C 76 (2016) 271 [arXiv:1603.03402] [INSPIRE].
  62. [62]
    LHCb collaboration, Measurement of forward W and Z boson production in association with jets in proton-proton collisions at \( \sqrt{s}=8 \) TeV, JHEP 05 (2016) 131 [arXiv:1605.00951] [INSPIRE].

Copyright information

© The Author(s) 2018

Authors and Affiliations

  • Michael Klasen
    • 1
  • Christian Klein-Bösing
    • 2
    • 3
  • Hendrik Poppenborg
    • 2
  1. 1.Institut für Theoretische PhysikWestfälische Wilhelms-Universität MünsterMünsterGermany
  2. 2.Institut für KernphysikWestfälische Wilhelms-Universität MünsterMünsterGermany
  3. 3.ExtreMe Matter Institute EMMI, GSI Helmholtzzentrum für SchwerionenforschungDarmstadtGermany

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