Rivet analyses

Kinematic distributions in D⁺ → K⁻π⁺e⁺ν_e

Experiment: BESIII (BEPC)

Inspire ID: 1411645

Status: VALIDATED

Authors: - Peter Richardson

References: - Phys.Rev.D 94 (2016) 3, 032001

Beams: * *

Beam energies: ANY

Run details: - Any process producing D+

Measurement of the kinematic distributions in D⁺ → K⁻π⁺e⁺ν_e by BES-III. N.B. Although there is some data in HEPDATA it is not physical and therefore the data were read from the paper and may not have been corrected for acceptance.

Source code:`BESIII_2016_I1411645.cc`

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

namespace Rivet {


  /// @brief D+ -> K- pi+ e+ nu_e
  class BESIII_2016_I1411645 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(BESIII_2016_I1411645);


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

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

      // Initialise and register projections
      UnstableParticles ufs = UnstableParticles(Cuts::pid==411);
      declare(ufs, "UFS");
      DecayedParticles DP(ufs);
      DP.addStable(PID::PI0);
      DP.addStable(PID::K0S);
      DP.addStable(PID::ETA);
      DP.addStable(PID::ETAPRIME);
      declare(DP, "DP");
      
      // Book histograms
      for(unsigned int ix=0;ix<6;++ix)
    book(_h[ix],3,1,1+ix);
    }


    /// Perform the per-event analysis
    void analyze(const Event& event) {
      static const map<PdgId,unsigned int> & mode = { { -321,1}, { 211,1}, {-11,1}, { 12,1}};
      DecayedParticles DP = apply<DecayedParticles>(event, "DP");
      // loop over particles
      for(unsigned int ix=0;ix<DP.decaying().size();++ix) {
    if ( !DP.modeMatches(ix,4,mode) ) continue;
        const Particle & Km = DP.decayProducts()[ix].at(-321)[0];
        const Particle & pip= DP.decayProducts()[ix].at( 211)[0];
        const Particle & ep = DP.decayProducts()[ix].at( -11)[0];
        const Particle & nue= DP.decayProducts()[ix].at(  12)[0];
        FourMomentum pKstar = Km.momentum()+pip.momentum(); 
        _h[0]->fill(pKstar.mass());
        _h[1]->fill(pKstar.mass());
    FourMomentum qq = DP.decaying()[ix].momentum()-pKstar;
    _h[2]->fill(qq.mass2());
    // boost momenta to DP rest frame
    LorentzTransform boost = LorentzTransform::mkFrameTransformFromBeta(DP.decaying()[ix].momentum().betaVec());
    FourMomentum pKS = boost.transform(pKstar);
    Matrix3 ptoz(-pKS.p3().unit(), Vector3(0,0,1));
    boost.preMult(ptoz);
    // the momenta in frane to W along z
    FourMomentum pD  = boost.transform(DP.decaying()[ix].momentum());
    FourMomentum pK  = boost.transform(Km .momentum());
    FourMomentum ppi = boost.transform(pip.momentum());
    FourMomentum pe  = boost.transform(ep .momentum());
    FourMomentum pnu = boost.transform(nue.momentum());
    pKstar = pK+ppi;
    qq = pD-pKstar;
    LorentzTransform boostK = LorentzTransform::mkFrameTransformFromBeta(pKstar.betaVec());
        Vector3 axisK = boostK.transform(pK).p3().unit();
        _h[4]->fill(axisK.dot(pKstar.p3().unit()));
        LorentzTransform boostW = LorentzTransform::mkFrameTransformFromBeta(    qq.betaVec());
        Vector3 axisE = boostW.transform(pe).p3().unit();
        _h[3]->fill(axisE.dot(qq.p3().unit()));
        axisK.setZ(0.);
        axisE.setZ(0.);
        double chi = atan2(axisE.cross(axisK).dot(qq.p3().unit()), axisE.dot(axisK));
        _h[5]->fill(chi);
      }
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      for(unsigned int ix=0;ix<6;++ix)
    normalize(_h[ix]);
    }

    /// @}


    /// @name Histograms
    /// @{
    Histo1DPtr _h[6];
    /// @}


  };


  RIVET_DECLARE_PLUGIN(BESIII_2016_I1411645);

}

Rivet analyses

Kinematic distributions in D+ → K−π+e+νe

Source code:BESIII_2016_I1411645.cc

Kinematic distributions in D⁺ → K⁻π⁺e⁺ν_e

Source code:`BESIII_2016_I1411645.cc`