Rivet analyses

e⁺e⁻ → D_s⁻D̄^(*)0K⁻+c.c. at $\sqrt{s}=4.6$ GeV

Experiment: BESIII (BEPC)

Inspire ID: 1711382

Status: VALIDATED NOHEPDATA

Authors: - Peter Richardson

References: - Chin.Phys.C 43 (2019) 3, 031001

Beams: e+ e-

Beam energies: (2.3, 2.3)GeV

Run details: - e+ e- > hadrons

Analysis of the resonant contributions to e⁺e⁻ → D_s⁻D̄^(*)0K⁻+c.c. at 4.6 GeV by the BESIII collaboration.

Source code:`BESIII_2018_I1711382.cc`

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

namespace Rivet {


  /// @brief e+ e- -> Ds+ Dbar0(*) K-
  class BESIII_2018_I1711382 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(BESIII_2018_I1711382);


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

    /// Book histograms and initialise projections before the run
    void init() {
      // projections
      declare(FinalState(), "FS");
      // histograms
      for (unsigned int ix = 0; ix < 4; ++ix) {
        book(_h_sigma[ix], 1, 1, 1 + ix);
      }
      book(_h_cTheta, 2, 1, 1);
    }


    /// Perform the per-event analysis
    void analyze(const Event& event) {
      Particles fs = apply<FinalState>(event, "FS").particles();
      Particles DS, D0, other;
      // first find the kaon and Ds
      for (const Particle& p : fs) {
        Particle parent = p;
        while (!parent.parents().empty()) {
          parent = parent.parents()[0];
          if (parent.abspid() == PID::DSPLUS || parent.abspid() == PID::D0) break;
        }
        if (parent.abspid() != PID::DSPLUS && parent.abspid() != PID::D0) {
          other.push_back(p);
          continue;
        }
        bool found = false;
        for (auto& D : parent.abspid() == PID::DSPLUS ? DS : D0) {
          // D already in list
          if (fuzzyEquals(D.mom(), parent.mom())) {
            found = true;
            break;
          }
        }
        if (!found) {
          (parent.abspid() == PID::DSPLUS ? DS : D0).push_back(parent);
        }
      }
      // Ds and D0, one particle and one anti particle
      if (DS.size() != 1 || D0.size() != 1 || DS[0].pid() * D0[0].pid() > 0) vetoEvent;
      int iK = DS[0].pid() > 0 ? -321 : 321;
      if (other.size() == 1 && other[0].pid() == iK) {
        _h_sigma[1]->fill("4.6"s);
        if (other[0].parents()[0].abspid() == 435 && D0[0].parents()[0].abspid() == 435) {
          _h_sigma[3]->fill("4.6"s);
          FourMomentum pDs2 = D0[0].momentum() + other[0].momentum();
          LorentzTransform boost = LorentzTransform::mkFrameTransformFromBeta(pDs2.betaVec());
          Vector3 axis1 = pDs2.p3().unit();
          Vector3 axis2 = boost.transform(other[0].momentum()).p3().unit();
          _h_cTheta->fill(abs(axis1.dot(axis2)));
        }
      }
      else if (D0[0].parents()[0].abspid() == 423) {
        bool Dstar = true;
        for (const Particle& p : other) {
          if (p.parents()[0].abspid() != 423 && p.pid() != iK) {
            Dstar = false;
            break;
          }
        }
        if (Dstar) {
          _h_sigma[0]->fill("4.6"s);
          if (D0[0].parents()[0].parents()[0].abspid() == 10433) {
            _h_sigma[2]->fill("4.6"s);
          }
        }
      }
    }

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

    /// @}


    /// @name Histograms
    /// @{
    BinnedHistoPtr<string> _h_sigma[4];
    Histo1DPtr _h_cTheta;
    /// @}
  };


  RIVET_DECLARE_PLUGIN(BESIII_2018_I1711382);

}

Rivet analyses

e+e− → Ds−D̄(*)0K−+c.c. at $\sqrt{s}=4.6$ GeV

Source code:BESIII_2018_I1711382.cc

e⁺e⁻ → D_s⁻D̄^(*)0K⁻+c.c. at $\sqrt{s}=4.6$ GeV

Source code:`BESIII_2018_I1711382.cc`