Rivet analyses

Mass distribution in Ξ_c⁺ → Ξ⁻π⁺π⁺

Experiment: BELLE (KEKB)

Inspire ID: 1698390

Status: VALIDATED

Authors: - Peter Richardson

References: none listed

Beams: * *

Beam energies: ANY

Run details: - Any process producing Xi_c

Measurement of the Ξ⁻π⁺ mass distribution in Ξ_c⁺ → Ξ⁻π⁺π⁺. N.B. data read from figure in paper and background extracted using line on the figure subtracted.

Source code:`BELLE_2018_I1698390.cc`

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

namespace Rivet {


  /// @brief Xi_c -> xi pi pi
  class BELLE_2018_I1698390 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(BELLE_2018_I1698390);


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

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

    void findDecay(int & sign, const Particle & parent, Particles & xi, Particles & pi,
           unsigned int & nstable) {
      for(const Particle & p : parent.children()) {
    if(p.pid()==sign*3312) {
      ++nstable;
      xi.push_back(p);
    }
    else if(p.pid()==sign*211) {
      ++nstable;
      pi.push_back(p);
    }
    else if(p.children().empty())
      ++nstable;
    else
      findDecay(sign,p,xi,pi,nstable);
      }
    }


    /// Perform the per-event analysis
    void analyze(const Event& event) {
      for(const Particle & p : apply<UnstableParticles>(event,"UFS").particles(Cuts::abspid==4232)) {
    int sign = p.pid()/p.abspid();
    Particles xi,pi;
    unsigned int nstable(0);
    findDecay(sign,p,xi,pi,nstable);
    LorentzTransform boost = LorentzTransform::mkFrameTransformFromBeta(p.momentum().betaVec());
    if(nstable==3&&xi.size()==1&&pi.size()==2) {
      double p1 = boost.transform(pi[0].momentum()).p3().mod();
      double p2 = boost.transform(pi[1].momentum()).p3().mod();
      double mass = p1>p2 ?
        (pi[1].momentum()+xi[0].momentum()).mass() :
        (pi[0].momentum()+xi[0].momentum()).mass();
      _h->fill(mass);
    }
      }
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      normalize(_h);
    }

    /// @}


    /// @name Histograms
    /// @{
    Histo1DPtr _h;
    /// @}


  };


  RIVET_DECLARE_PLUGIN(BELLE_2018_I1698390);

}

Rivet analyses

Mass distribution in Ξc+ → Ξ−π+π+

Source code:BELLE_2018_I1698390.cc

Mass distribution in Ξ_c⁺ → Ξ⁻π⁺π⁺

Source code:`BELLE_2018_I1698390.cc`