rivet is hosted by Hepforge, IPPP Durham

Rivet analyses reference

BESIII_2023_I2661512

Cross section for $e^+e^-\to\Delta^{++}\bar{p}\pi^-+\text{c.c}$ for $\sqrt{s}=2.3094\to2.6464$
Experiment: BESIII (BEPC)
Inspire ID: 2661512
Status: VALIDATED NOHEPDATA
Authors:
  • Peter Richardson
References:
  • Phys.Rev.D 108 (2023) 7, 072010
  • arXiv: 2305.12166
Beams: e+ e-
Beam energies: (1.2, 1.2); (1.2, 1.2); (1.2, 1.2); (1.2, 1.2); (1.3, 1.3); (1.3, 1.3); (1.3, 1.3) GeV
Run details:
  • e+e- to hadrons

Measurement of the cross section for $e^+e^-\to\Delta^{++}\bar{p}\pi^-+\text{c.c}$ for $\sqrt{s}=2.3094\to2.6464$ by the BESIII collaboration. Beam energy must be specified as analysis option "ENERGY" when rivet-merging samples.

Source code: BESIII_2023_I2661512.cc
  1// -*- C++ -*-
  2#include "Rivet/Analysis.hh"
  3#include "Rivet/Projections/FinalState.hh"
  4#include "Rivet/Projections/UnstableParticles.hh"
  5
  6namespace Rivet {
  7
  8
  9  /// @brief e+e- > Delta++ pbar- pi-
 10  class BESIII_2023_I2661512 : public Analysis {
 11  public:
 12
 13    /// Constructor
 14    RIVET_DEFAULT_ANALYSIS_CTOR(BESIII_2023_I2661512);
 15
 16
 17    /// @name Analysis methods
 18    /// @{
 19
 20    /// Book histograms and initialise projections before the run
 21    void init() {
 22      declare(FinalState(), "FS");
 23      declare(UnstableParticles(Cuts::abspid==2224), "UFS");
 24      vector<string> energies({"2.3094", "2.3864", "2.396", "2.5", "2.6444", "2.6464"});
 25      bool matched=false;
 26      for(const string& en : energies) {
 27        double end = std::stod(en)*GeV;
 28        if(isCompatibleWithSqrtS(end)) {
 29          _ecms = en;
 30          matched=true;
 31          break;
 32        }
 33      }
 34      if(!_ecms.empty())
 35        book(_sigma[0],1,1,1);
 36      if(isCompatibleWithSqrtS(2.6454)) {
 37        book(_sigma[1],2,1,1);
 38        matched=true;
 39      }
 40      if(!matched) MSG_ERROR("Beam energy incompatible with analysis.");
 41    }
 42
 43    void findChildren(const Particle& p,map<long,int>& nRes, int& ncount) {
 44      for (const Particle &child : p.children()) {
 45        if (child.children().empty()) {
 46          --nRes[child.pid()];
 47          --ncount;
 48        }
 49        else {
 50          findChildren(child, nRes, ncount);
 51        }
 52      }
 53    }
 54
 55    /// Perform the per-event analysis
 56    void analyze(const Event& event) {
 57      const FinalState& fs = apply<FinalState>(event, "FS");
 58      map<long,int> nCount;
 59      int ntotal(0);
 60      for (const Particle& p : fs.particles()) {
 61        nCount[p.pid()] += 1;
 62        ++ntotal;
 63      }
 64      // loop over delta++
 65      for (const Particle& p : apply<FinalState>(event, "UFS").particles()) {
 66        int sign =-p.pid()/p.abspid();
 67        map<long,int> nRes = nCount;
 68        int ncount = ntotal;
 69        findChildren(p, nRes, ncount);
 70        bool matched = true;
 71        for (const auto& val : nRes) {
 72          if (val.first== 211*sign || val.first==2212*sign) {
 73            if (val.second !=1) {
 74              matched = false;
 75              break;
 76            }
 77          }
 78          else if (val.second!=0) {
 79            matched = false;
 80            break;
 81          }
 82        }
 83        if (matched) {
 84	  if(_sigma[0]) _sigma[0]->fill(_ecms);
 85          if(_sigma[1]) _sigma[1]->fill(string("2.6454"));
 86          break;
 87        }
 88      }
 89    }
 90
 91
 92    /// Normalise histograms etc., after the run
 93    void finalize() {
 94      double fact = crossSection()/ sumOfWeights() /picobarn;
 95      for(unsigned int ix=0;ix<2;++ix) scale(_sigma[ix],fact);
 96    }
 97
 98    /// @}
 99
100
101    /// @name Histograms
102    /// @{
103    BinnedHistoPtr<string> _sigma[2];
104    string _ecms;
105    /// @}
106
107
108  };
109
110
111  RIVET_DECLARE_PLUGIN(BESIII_2023_I2661512);
112
113}