1// -*- C++ -*-
 2#include "Rivet/Analysis.hh"
 3#include "Rivet/Projections/UnstableParticles.hh"
 4
 5namespace Rivet {
 6
 7
 8  /// @brief B_s production at 7 TeV
 9  class CMS_2011_I914325 : public Analysis {
10  public:
11
12    /// Constructor
13    RIVET_DEFAULT_ANALYSIS_CTOR(CMS_2011_I914325);
14
15
16    /// @name Analysis methods
17    /// @{
18
19    /// Book histograms and initialise projections before the run
20    void init() {
21      // projection
22      declare(UnstableParticles(), "UFS");
23      // histograms
24      book(_h_sigma,1,1,1);
25      book(_h_pT   ,2,1,1);
26      book(_h_y    ,3,1,1);
27    }
28
29
30    /// Perform the per-event analysis
31    void analyze(const Event& event) {
32      // Final state of unstable particles to get particle spectra
33      const UnstableParticles& ufs = apply<UnstableParticles>(event, "UFS");
34      // loop over onium states
35      for (const Particle& p : ufs.particles(Cuts::abspid==531)) {
36        // skip copies due mixing
37        if (p.children().size()==1 && p.children()[0].abspid()==531) continue;
38        // rapidity and pT
39        const double y = p.absrap();
40        if (y>2.4) continue;
41        const double pT = p.perp();
42        if (pT<8. || pT>50.) continue;
43        _h_sigma->fill(29.);
44        _h_pT->fill(pT);
45        _h_y->fill(y);
46      }
47    }
48
49
50    /// Normalise histograms etc., after the run
51    void finalize() {
52      // br for J/psi phi (PDG 2021)
53      const double br = 1.08e-3;
54      // 0.5 from particle/antiparticle
55      const double fact = 0.5*br*crossSection()/nanobarn/sumOfWeights();
56      // remove the bin width as total cross section
57      scale(_h_sigma, fact*42.);
58      // normal differential cross sections
59      scale(_h_pT, fact);
60      scale(_h_y, fact);
61    }
62
63    /// @}
64
65
66    /// @name Histograms
67    /// @{
68    Histo1DPtr _h_sigma,_h_pT,_h_y;
69    /// @}
70
71
72  };
73
74
75  RIVET_DECLARE_PLUGIN(CMS_2011_I914325);
76
77}