1// -*- C++ -*-
 2#include "Rivet/Analysis.hh"
 3#include "Rivet/Projections/UnstableParticles.hh"
 4
 5namespace Rivet {
 6
 7
 8  /// @brief chi_c at 7 TeV
 9  class CMS_2012_I1189050 : public Analysis {
10  public:
11
12    /// Constructor
13    RIVET_DEFAULT_ANALYSIS_CTOR(CMS_2012_I1189050);
14
15
16    /// @name Analysis methods
17    /// @{
18
19    /// Book histograms and initialise projections before the run
20    void init() {
21      declare(UnstableParticles(), "UFS");
22      for(unsigned int ichi=0; ichi<2; ++ichi) {
23        for (unsigned int ipT=0; ipT<2; ++ipT) {
24          book(_h_chi[ichi][ipT], "TMP/h_CHI_"+toString(ichi)+"_"+toString(ipT), refData(1,1,1));
25        }
26      }
27    }
28
29
30    /// Perform the per-event analysis
31    void analyze(const Event& event) {
32
33      // Final state of unstable particles to get particle spectra
34      const UnstableParticles& ufs = apply<UnstableParticles>(event, "UFS");
35
36      for (const Particle& p : ufs.particles(Cuts::pid==20443 || Cuts::pid==445)) {
37        // prompt
38        if (p.fromBottom()) continue;
39        // J/psi /gamma mode
40        if (p.children().size()!=2) continue;
41        Particle Jpsi,gamma;
42        if (p.children()[0].pid()==22 && p.children()[1].pid()==443) {
43          Jpsi  = p.children()[1];
44          gamma = p.children()[0];
45        }
46        else if (p.children()[1].pid()==22 && p.children()[0].pid()==443) {
47          Jpsi  = p.children()[0];
48          gamma = p.children()[1];
49        }
50        else {
51          continue;
52        }
53        if (Jpsi.absrap()>1.) continue;
54        const double xp=Jpsi.perp();
55        unsigned int ichi = p.pid()==20443 ? 0 : 1;
56        if (gamma.perp()>0.5) {
57          _h_chi[ichi][0]->fill(xp);
58        }
59        _h_chi[ichi][1]->fill(xp);
60      }
61    }
62
63
64    /// Normalise histograms etc., after the run
65    void finalize() {
66      // chi_c to gamma J/psi branching ratios from PDG 2021
67      const vector<double> br = {0.343,0.190};
68      // no br correction fiduical region
69      Estimate1DPtr tmp;
70      book(tmp, 1, 1, 1);
71      divide(_h_chi[1][0], _h_chi[0][0], tmp);
72      // br correction fiduical region
73      book(tmp, 2, 1, 1);
74      divide(_h_chi[1][0], _h_chi[0][0], tmp);
75      tmp->scale(br[0]/br[1]);
76      // no br correction  pT gamma >0
77      book(tmp, 3, 1, 1);
78      divide(_h_chi[1][1], _h_chi[0][1], tmp);
79    }
80
81    /// @}
82
83
84    /// @name Histograms
85    /// @{
86    Histo1DPtr _h_chi[2][2];
87    /// @}
88
89
90  };
91
92
93  RIVET_DECLARE_PLUGIN(CMS_2012_I1189050);
94
95}