Rivet analyses

pK− mass distribution in Λc+ → pK−e+νe

Experiment: BESIII (BEPC)

Inspire ID: 2122399

Status: VALIDATED NOHEPDATA

Authors: - Peter Richardson

References: - arXiv: 2207.11483

Beams: * *

Beam energies: ANY

Run details: - Any process producing Lambda_c+

Measurement of the pK− mass distribution in Λc+ → pK−e+νe by BES-III. N.B. The data were read from the paper and may not have been corrected for acceptance.

Source code:BESIII_2022_I2122399.cc

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

namespace Rivet {


  /// @brief Lambda_c+ -> p K- e+ nu_e
  class BESIII_2022_I2122399 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(BESIII_2022_I2122399);


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

    /// Book histograms and initialise projections before the run
    void init() {
      // Initialise and register projections
      UnstableParticles ufs = UnstableParticles(Cuts::pid == 4122);
      declare(ufs, "UFS");
      DecayedParticles LambdaC(ufs);
      LambdaC.addStable(PID::PI0);
      LambdaC.addStable(PID::K0S);
      LambdaC.addStable(PID::ETA);
      LambdaC.addStable(PID::ETAPRIME);
      declare(LambdaC, "LambdaC");

      // Book histogram
      book(_h, 1, 1, 1);
    }


    /// Perform the per-event analysis
    void analyze(const Event& event) {
      static const map<PdgId, unsigned int>& mode = {{-321, 1}, {2212, 1}, {-11, 1}, {12, 1}};
      DecayedParticles LambdaC = apply<DecayedParticles>(event, "LambdaC");
      // loop over particles
      for (unsigned int ix = 0; ix < LambdaC.decaying().size(); ++ix) {
        if (!LambdaC.modeMatches(ix, 4, mode)) continue;
        const Particle& Km = LambdaC.decayProducts()[ix].at(-321)[0];
        const Particle& pp = LambdaC.decayProducts()[ix].at(2212)[0];
        _h->fill((Km.momentum() + pp.momentum()).mass());
      }
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      normalize(_h, 1., false);
    }

    /// @}


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


  RIVET_DECLARE_PLUGIN(BESIII_2022_I2122399);

}