Rivet analyses

Cross section for Bs(*)0B̄s(*)0 at $\sqrt{s}=10.86$ GeV

Experiment: BELLE (KEKB)

Inspire ID: 1358399

Status: VALIDATED NOHEPDATA

Authors: - Peter Richardson

References: - Phys.Rev.D 92 (2015) 7, 072013

Beams: e+ e-

Beam energies: (5.4, 5.4)GeV

Run details: none listed

Measurement of the cross section for Bs(*)0B̄s(*)0 at $\sqrt{s}=10.86$ GeV.

Source code:BELLE_2015_I1358399.cc

// -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/FinalState.hh"
#include "Rivet/Projections/UnstableParticles.hh"

namespace Rivet {


  /// @brief e+ e- > B(*)s B(*)s
  class BELLE_2015_I1358399 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(BELLE_2015_I1358399);


    /// @name Analysis methods
    /// @{

    /// Book histograms and initialise projections before the run
    void init() {
      // Initialise and register projections
      declare(FinalState(), "FS");
      declare(UnstableParticles(), "UFS");
      // histograms
      book(_h, 1, 1, 1);
    }

    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;
      }
      // extract botton hadrons
      Particles bHadrons = apply<FinalState>(event, "UFS")
                               .particles(Cuts::abspid == 531 or Cuts::abspid == 533);
      for (unsigned int ix = 0; ix < bHadrons.size(); ++ix) {
        if (bHadrons[ix].parents()[0].abspid() == 531 || bHadrons[ix].parents()[0].abspid() == 533) continue;
        map<long, int> nRes = nCount;
        int ncount = ntotal;
        findChildren(bHadrons[ix], nRes, ncount);
        bool matched = false;
        for (unsigned int iy = ix + 1; iy < bHadrons.size(); ++iy) {
          if (bHadrons[iy].parents()[0].abspid() == 531 || bHadrons[iy].parents()[0].abspid() == 533)
            continue;
          map<long, int> nRes2 = nRes;
          int ncount2 = ncount;
          findChildren(bHadrons[iy], nRes2, ncount2);
          if (ncount2 != 0) continue;
          matched = true;
          for (const auto& val : nRes2) {
            if (val.second != 0) {
              matched = false;
              break;
            }
          }
          if (matched) {
            _h->fill("10.86"s);
            break;
          }
        }
        if (matched) break;
      }
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      scale(_h, crossSection() / sumOfWeights() / picobarn);
    }

    /// @}


    /// @name Histograms
    /// @{
    BinnedHistoPtr<string> _h;
    /// @}
  };


  RIVET_DECLARE_PLUGIN(BELLE_2015_I1358399);

}