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LHCB_2014_I1315113

Relative production rates of $\chi_{b1}(1P)$ to $\chi_{b2}(1P)$ at 7 TeV
Experiment: LHCB (LHC)
Inspire ID: 1315113
Status: VALIDATED
Authors:
  • Peter Richardson
References:
  • JHEP 10 (2014) 088
Beams: p+ p+
Beam energies: (3500.0, 3500.0) GeV
Run details:
  • chi_b(1,2) production

Measurement of the relative rates of prompt $\chi_{b1}$ to $\chi_{b2}$ production at 7 TeV using the decay to $\Upsilon\gamma$ by the LHCb collaboration.

Source code: LHCB_2014_I1315113.cc
 1// -*- C++ -*-
 2#include "Rivet/Analysis.hh"
 3#include "Rivet/Projections/UnstableParticles.hh"
 4
 5namespace Rivet {
 6
 7
 8  /// @brief chi_b production at 7 TeV
 9  class LHCB_2014_I1315113 : public Analysis {
10  public:
11
12    /// Constructor
13    RIVET_DEFAULT_ANALYSIS_CTOR(LHCB_2014_I1315113);
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	book(_h_chi[ichi],"TMP/h_CHI_"+toString(ichi),refData(1,1,1));
24      }
25    }
26
27
28    /// Perform the per-event analysis
29    void analyze(const Event& event) {
30      const UnstableParticles& ufs = apply<UnstableParticles>(event, "UFS");
31
32      for (const Particle& p : ufs.particles(Cuts::pid==20553 ||
33					     Cuts::pid==555)) {
34	// Upsilon /gamma mode
35	if(p.children().size()!=2) continue;
36	Particle ups;
37	if(p.children()[0].pid()==22 && p.children()[1].pid()==553) {
38	  ups  = p.children()[1];
39	}
40	else if(p.children()[1].pid()==22 && p.children()[0].pid()==553) {
41	  ups  = p.children()[0];
42	}
43	else
44	  continue;
45	double absrap=ups.absrap();
46	if(absrap<2. || absrap>4.5) continue;
47	unsigned int ichi = p.pid()==20553 ? 0 : 1;
48	_h_chi[ichi]->fill(ups.perp());
49      }
50    }
51
52
53    /// Normalise histograms etc., after the run
54    void finalize() {
55      vector<double> br = {.352,0.18};
56      for(unsigned int ix=0;ix<2;++ix)
57	scale(_h_chi[ix],1./br[ix]);
58      Estimate1DPtr tmp;
59      book(tmp,1,1,1);
60      divide(_h_chi[0],_h_chi[1],tmp);
61      tmp->scale(br[1]/br[0]);
62    }
63
64    /// @}
65
66
67    /// @name Histograms
68    /// @{
69    Histo1DPtr _h_chi[2];
70    /// @}
71
72
73  };
74
75
76  RIVET_DECLARE_PLUGIN(LHCB_2014_I1315113);
77
78}