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## Rivet analyses reference

### LHCF_2018_I1518782

Measurement of forward photon production cross-section in proton-proton collisions at $\mathrm{\sqrt{s}=13\,TeV}$ with the LHCf detector
Experiment: LHCF (LHC)
Inspire ID: 1518782
Status: VALIDATED
Authors:
• Eugenio Berti
• LHCf collaboration
References:
Beams: p+ p+
Beam energies: (6500.0, 6500.0) GeV
Run details:
• Inclusive differential production cross section of forward photons produced in p-p collisions at $\mathrm{\sqrt{s}=13\,TeV}$. Cross section is expressed as a function of energy in two different pseudorapidity regions, namely $\eta>10.94$ and $8.81<\eta<8.99$. The measurements refer to all photons directly produced in the collisions or resulting from the decay of short life particles ($\mathrm{c \tau<1\,cm}$).

In this paper, we report the production cross-section of forward photons in the pseudorapidity regions of $\eta>10.94$ and $8.99>\eta>8.81$, measured by the LHCf experiment with proton-proton collisions at $\mathrm{\sqrt{s}=13\,TeV}$. The results from the analysis of $\mathrm{0.191\,nb^{-1}}$ of data obtained in June 2015 are compared to the predictions of several hadronic interaction models that are used in air-shower simulations for ultra-high-energy cosmic rays. Although none of the models agree perfectly with the data, EPOS-LHC shows the best agreement with the experimental data among the models.

Source code: LHCF_2018_I1518782.cc
 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 // -*- C++ -*- #include "Rivet/Analysis.hh" #include "Rivet/Projections/Beam.hh" #include "Rivet/Tools/BinnedHistogram.hh" #include "Rivet/Projections/UnstableParticles.hh" namespace Rivet { /// @brief Forward photon production cross-section at 13 TeV class LHCF_2018_I1518782 : public Analysis { public: /// Constructor DEFAULT_RIVET_ANALYSIS_CTOR(LHCF_2018_I1518782); /// @name Analysis methods //@{ /// Book histograms and initialise projections before the run void init() { // Initialise and register projections declare(Beam(), "Beam"); declare(FinalState(), "FS"); // Book histograms book(_h_n_en_eta1, 1, 1, 1); book(_h_n_en_eta2, 2, 1, 1); } /// Perform the per-event analysis void analyze(const Event& event) { Particles fs_particles = apply (event, "FS").particles(); for (const Particle& p : fs_particles) { // Select photons above threshold if (p.abspid() != PID::PHOTON) continue; if (p.E() < 200*GeV) continue; // Double analysis efficiency with a two-sided LHCf const double eta = abs(p.eta()); const double energy = p.E()/GeV; // Fill histograms if ( eta > 10.94 ) { _h_n_en_eta1->fill(energy); } else if (eta > 8.81 && eta < 8.99) { _h_n_en_eta2->fill(energy); } } } /// Normalise histograms etc., after the run void finalize() { // Norm to cross-section scale(_h_n_en_eta1, crossSection()/millibarn/sumOfWeights()/2.); scale(_h_n_en_eta2, crossSection()/millibarn/sumOfWeights()/2.); } //@} private: /// @name Histograms //@{ Histo1DPtr _h_n_en_eta1, _h_n_en_eta2; //@} }; DECLARE_RIVET_PLUGIN(LHCF_2018_I1518782); }