The production of isolated photons in PbPb and pp collisions at $\sqrt{s_{\mathrm{NN}}}=$ 5.02 TeV

Abstract

The transverse energy ($E_{\mathrm{T}}^{\gamma }$) spectra of photons isolated from other particles are measured using proton-proton (pp) and lead-lead (PbPb) collisions at the LHC at $\sqrt{s_{\mathrm{NN}}}=$ 5.02 TeV with integrated luminosities of 27.4 pb${}^{-1}$and 404 $\mu$b${}^{-1}$ for pp and PbPb data, respectively. The results are presented for photons with 25 $<$ $E_{\mathrm{T}}^{\gamma }$ $<$ 200 GeV in the pseudorapidity range $|\eta |$ $<$ 1.44, and for different centrality intervals for PbPb collisions. Photon production in PbPb collisions is consistent with that in pp collisions scaled by the number of binary nucleon-nucleon collisions, demonstrating that photons do not interact with the quark-gluon plasma. Therefore, isolated photons can provide information about the initial energy of the associated parton in photon+jet measurements. The results are compared with predictions from the next-to-leading-order JETPHOX generator for different parton distribution functions (PDFs) and nuclear PDFs (nPDFs). The comparisons can help to constrain the nPDFs global fits.

arXiv commentReplaced with the published version. Added the journal reference and the DOI. All the figures and tables can be found at http://cms-results.web.cern.ch/cms-results/public-results/publications/HIN-18-016 (CMS Public Pages)

References in corpus (40)

• An Introduction to PYTHIA 8.2
• LHAPDF6: parton density access in the LHC precision era
• Glauber Modeling in High Energy Nuclear Collisions
• New parton distribution functions from a global analysis of quantum chromodynamics
• The chiral and deconfinement aspects of the QCD transition
• Is there still any Tc mystery in lattice QCD? Results with physical masses in the continuum limit III
• Heavy Ion Collisions: The Big Picture, and the Big Questions
• The CMS trigger system
• Observation and studies of jet quenching in PbPb collisions at nucleon-nucleon center-of-mass energy = 2.76 TeV
• Event generator tunes obtained from underlying event and multiparton scattering measurements
• nCTEQ15 - Global analysis of nuclear parton distributions with uncertainties in the CTEQ framework
• EPPS16: Nuclear parton distributions with LHC data
• A model of jet quenching in ultrarelativistic heavy ion collisions and high-pt hadron spectra at RHIC
• Determination of nuclear parton distribution functions and their uncertainties at next-to-leading order
• Nuclear parton distributions at next to leading order
• Performance of photon reconstruction and identification with the CMS detector in proton-proton collisions at sqrt(s) = 8 TeV
• Direct photon production in Pb-Pb collisions at $\sqrt{s_\rm{NN}}$ = 2.76 TeV
• Charged-particle nuclear modification factors in PbPb and pPb collisions at sqrt(s[NN]) = 5.02 TeV
• A new critical study of photon production in hadronic collisions
• Measurement of the Inclusive Upsilon production cross section in pp collisions at sqrt(s)=7 TeV
• Measurement of isolated photon production in pp and PbPb collisions at sqrt(sNN) = 2.76 TeV
• Measurement of nuclear modification factors of ${\rm Y}$(1S), ${\rm Y}$(2S), and ${\rm Y}$(3S) mesons in PbPb collisions at $\sqrt{s_{{}_{\mathrm{NN}}}}=$ 5.02 TeV
• Measurement of prompt and nonprompt charmonium suppression in PbPb collisions at 5.02 TeV
• Measurement of the inclusive isolated prompt photon cross-section in pp collisions at sqrt(s)= 7 TeV using 35 pb-1 of ATLAS data
• Measurement of the Differential Cross Section for Isolated Prompt Photon Production in pp Collisions at 7 TeV
• Measurement of the inclusive isolated prompt photon cross section in pp collisions at sqrt(s) = 7 TeV with the ATLAS detector using 4.6 fb-1
• Measurement of the Isolated Prompt Photon Production Cross Section in pp Collisions at sqrt(s) = 7 TeV
• Measurement of the inclusive isolated prompt photon cross section in $pp$ collisions at $\sqrt{s}=8$ TeV with the ATLAS detector
• Quarks and Gluon Fragmentation Functions into Photons
• Measurement of photon-jet transverse momentum correlations in 5.02 TeV Pb+Pb and $pp$ collisions with ATLAS
• 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
• Study of jet quenching with isolated-photon+jet correlations in PbPb and pp collisions at $\sqrt{s_{{}_{\mathrm{NN}}}}=$ 5.02 TeV
• Inclusive prompt photon production in nuclear collisions at RHIC and LHC
• Observation of medium induced modifications of jet fragmentation in PbPb collisions at $\sqrt{s_{\mathrm{NN}}}=$ 5.02 TeV using isolated-photon-tagged jets
• Sensitivity of isolated photon production at TeV hadron colliders to the gluon distribution in the proton
• Jet shapes of isolated photon-tagged jets in PbPb and pp collisions at $\sqrt{s_{\mathrm{NN}}}=$ 5.02 TeV
• Measurement of differential cross sections for inclusive isolated-photon and photon+jet production in proton-proton collisions at $\sqrt{s}=$ 13 TeV
• Measurement of the inclusive isolated photon production cross section in pp collisions at $\sqrt{s}$ = 7 TeV
• Measurement of prompt photon production in $\sqrt{s_{\mathrm{NN}}}=8.16$ TeV $p$+Pb collisions with ATLAS
• Single and Double Photonuclear Excitations in Pb+Pb Collisions at sqrt(s_NN) = 2.76 TeV at the CERN Large Hadron Collider

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• Evidence of medium response to hard probes using correlations of Z bosons with hadrons in heavy ion collisions
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