rivet is hosted by Hepforge, IPPP Durham

Rivet analyses reference

BESIII_2018_I1685535

Cross section for $e^+e^-\to\pi^+D^0D^{*-}$ +c.c. cross section between 4.05 and 4.60 GeV
Experiment: BESIII (BEPC)
Inspire ID: 1685535
Status: VALIDATED
Authors:
  • Peter Richardson
References:
  • Phys.Rev.Lett. 122 (2019) no.10, 102002
Beams: e+ e-
Beam energies: ANY
Run details:
  • e+e- to hadrons

Measurement of the cross section for $e^+e^-\to\pi^+D^0D^{*-}$ +c.c. cross section between 4.05 and 4.60 GeV by thew BEWS collaboration.

Source code: BESIII_2018_I1685535.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
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
// -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/FinalState.hh"
#include "Rivet/Projections/UnstableParticles.hh"

namespace Rivet {


  /// @brief Cross section for D0 D*- pi+ +c.c
  class BESIII_2018_I1685535 : public Analysis {
  public:

    /// Constructor
    DEFAULT_RIVET_ANALYSIS_CTOR(BESIII_2018_I1685535);


    /// @name Analysis methods
    //@{

    /// Book histograms and initialise projections before the run
    void init() {

      // Initialise and register projections
      declare(FinalState(), "FS");
      declare(UnstableParticles(), "UFS");
      book(_nD0, "/TMP/nD0");
    }

    void findChildren(const Particle & p,map<long,int> & nRes, int &ncount) {
      for (const Particle &child : p.children()) {
	if(child.children().empty()) {
	  nRes[child.pid()]-=1;
	  --ncount;
	}
	else
	  findChildren(child,nRes,ncount);
      }
    }

    /// Perform the per-event analysis
    void analyze(const Event& event) {
      const FinalState& fs = apply<FinalState>(event, "FS");

      map<long,int> nCount;
      int ntotal(0);
      for (const Particle& p : fs.particles()) {
	nCount[p.pid()] += 1;
	++ntotal;
      }
      const FinalState& ufs = apply<FinalState>(event, "UFS");


      for(unsigned int ix=0;ix<ufs.particles().size();++ix) {
	const Particle& p1 = ufs.particles()[ix];
	if(abs(p1.pid())!=421) continue;
	map<long,int> nRes = nCount;
	int ncount = ntotal;
	findChildren(p1,nRes,ncount);
	bool matched=false;
	int id2 = p1.pid()>0 ? -413 :  413;
	int ipi = p1.pid()>0 ?  211 : -211;
	for(unsigned int iy=0;iy<ufs.particles().size();++iy) {
	  if(ix==iy) continue;
	  const Particle& p2 = ufs.particles()[iy];
	  if(p2.pid()!=id2) continue;
	  map<long,int> nRes2 = nRes;
	  int ncount2 = ncount;
	  findChildren(p2,nRes2,ncount2);
	  if(ncount2!=1) continue;
	  matched=true;
	  for(auto const & val : nRes2) {
	    if(val.first==ipi) {
	      if(val.second!=1) {
		matched = false;
		break;
	      }
	    }
	    else if(val.second!=0) {
	      matched = false;
	      break;
	    }
	  }
	  if(matched) break;
	}
	if(matched)
	  _nD0->fill();
      }
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      double sigma = _nD0->val();
      double error = _nD0->err();
      sigma *= crossSection()/ sumOfWeights() /nanobarn;
      error *= crossSection()/ sumOfWeights() /nanobarn;
      for(unsigned int ix=1;ix<3;++ix) {
	Scatter2D temphisto(refData(ix, 1, 1));
	Scatter2DPtr  mult;
	book(mult, ix, 1, 1);
	for (size_t b = 0; b < temphisto.numPoints(); b++) {
	  const double x  = temphisto.point(b).x();
	  pair<double,double> ex = temphisto.point(b).xErrs();
	  pair<double,double> ex2 = ex;
	  if(ex2.first ==0.) ex2. first=0.0001;
	  if(ex2.second==0.) ex2.second=0.0001;
	  if (inRange(sqrtS()/GeV, x-ex2.first, x+ex2.second)) {
	    mult->addPoint(x, sigma, ex, make_pair(error,error));
	  }
	  else {
	    mult->addPoint(x, 0., ex, make_pair(0.,.0));
	  }
	}
      }
    }

    //@}


    /// @name Histograms
    //@{
    CounterPtr _nD0;
    //@}


  };


  DECLARE_RIVET_PLUGIN(BESIII_2018_I1685535);

}