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KLOE_2008_I791841

Cross section for $\pi^+\pi^-2\pi^0$ and $2\pi^0\gamma$ near the $\phi$ mass
Experiment: KLOE (DAPHNE)
Inspire ID: 791841
Status: VALIDATED
Authors:
  • Peter Richardson
References:
  • Phys.Lett. B669 (2008) 223-228, 2008
Beams: e+ e-
Beam energies: ANY
Run details:
  • e+e- to hadrons

Measurement of the cross section for $\pi^+\pi^-2\pi^0$ and $2\pi^0\gamma$ near the $\phi$ mass

Source code: KLOE_2008_I791841.cc
 1// -*- C++ -*-
 2#include "Rivet/Analysis.hh"
 3#include "Rivet/Projections/FinalState.hh"
 4
 5namespace Rivet {
 6
 7
 8  /// @brief Add a short analysis description here
 9  class KLOE_2008_I791841 : public Analysis {
10  public:
11
12    /// Constructor
13    RIVET_DEFAULT_ANALYSIS_CTOR(KLOE_2008_I791841);
14
15
16    /// @name Analysis methods
17    //@{
18
19    /// Book histograms and initialise projections before the run
20    void init() {
21      // Initialise and register projections
22      declare(FinalState(), "FS");
23      book(_n4pi, "TMP/4pi");
24      book(_n2pigamma, "TMP/2pigamma");
25    }
26
27
28    /// Perform the per-event analysis
29    void analyze(const Event& event) {
30      const FinalState& fs = apply<FinalState>(event, "FS");
31      
32      map<long,int> nCount;
33      int ntotal(0);
34      for (const Particle& p : fs.particles()) {
35	nCount[p.pid()] += 1;
36	++ntotal;
37      }
38      if(nCount[111]==2) {
39	if( nCount[211] == 1 && nCount[-211] == 1 )
40	  _n4pi->fill();
41	else if( nCount[22] == 1)
42	  _n2pigamma->fill();
43      }
44    }
45
46
47    /// Normalise histograms etc., after the run
48    void finalize() {
49      for(unsigned int ix=1;ix<3;++ix) {
50	double sigma = 0., error = 0.;
51	if(ix==1) {
52	  sigma = _n4pi->val();
53	  error = _n4pi->err();
54	}
55	else if(ix==2) {
56   	  sigma = _n2pigamma->val();
57	  error = _n2pigamma->err();
58        }
59	sigma *= crossSection()/ sumOfWeights() /nanobarn;
60	error *= crossSection()/ sumOfWeights() /nanobarn; 
61	Scatter2D temphisto(refData(ix, 1, 1));
62	Scatter2DPtr mult;
63	book(mult, ix, 1, 1);
64	for (size_t b = 0; b < temphisto.numPoints(); b++) {
65	  const double x  = temphisto.point(b).x();
66	  pair<double,double> ex = temphisto.point(b).xErrs();
67	  pair<double,double> ex2 = ex;
68	  if(ex2.first ==0.) ex2. first=0.0001;
69	  if(ex2.second==0.) ex2.second=0.0001;
70	  if (inRange(sqrtS()/MeV, x-ex2.first, x+ex2.second)) {
71	    mult->addPoint(x, sigma, ex, make_pair(error,error));
72	  }
73	  else {
74	    mult->addPoint(x, 0., ex, make_pair(0.,.0));
75	  }
76	}
77      }
78    }
79
80    //@}
81
82
83    /// @name Histograms
84    //@{
85    CounterPtr _n4pi,_n2pigamma;
86    //@}
87
88
89  };
90
91
92  // The hook for the plugin system
93  RIVET_DECLARE_PLUGIN(KLOE_2008_I791841);
94
95
96}