Rivet analyses

Spectra for Σc* + +, 0 at 10.58 GeV

Experiment: CLEOII (CESR)

Inspire ID: 424575

Status: VALIDATED

Authors: - Peter Richardson

References: - Phys.Rev.Lett. 78 (1997) 2304-2308

Beams: e+ e-

Beam energies: (5.3, 5.3)GeV

Run details: - e+e- to hadrons

Spectrum for the average of Σc*0 and Σc* + + produced at 10.58 GeV measured by CLEOII.

Source code:CLEOII_1997_I424575.cc

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

namespace Rivet {


  /// @brief Sigma*_c spectra
  class CLEOII_1997_I424575 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(CLEOII_1997_I424575);


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

    /// Book histograms and initialise projections before the run
    void init() {
      // projections
      declare(Beam(), "Beams");
      declare(UnstableParticles(), "UFS");
      // book histos
      book(_h_cTheta, 2, 1, 1);
      book(_h_x, 3, 1, 1);
    }


    /// Perform the per-event analysis
    void analyze(const Event& event) {
      // Get beams and average beam momentum
      const ParticlePair& beams = apply<Beam>(event, "Beams").beams();
      const double Emax = (beams.first.p3().mod() + beams.second.p3().mod()) / 2.0;
      const double Pmax = sqrt(sqr(Emax) - sqr(2.518));
      const UnstableParticles& ufs = apply<UnstableParticles>(event, "UFS");
      for (const Particle& p : ufs.particles(Cuts::abspid == 4114 or Cuts::abspid == 4224)) {
        // momentum fraction
        double xp = p.momentum().p3().mod() / Pmax;
        _h_x->fill(xp);
        if (p.children().size() != 2) continue;
        // decay angle
        Particle pi;
        int sign = p.pid() / p.abspid();
        if (p.abspid() == 4224) {
          if (p.children()[0].pid() == sign * 4122 && p.children()[1].pid() == sign * 211) {
            pi = p.children()[1];
          }
          else if (p.children()[1].pid() == sign * 4122 && p.children()[0].pid() == sign * 211) {
            pi = p.children()[0];
          }
          else
            continue;
        }
        else {
          if (p.children()[0].pid() == sign * 4122 && p.children()[1].pid() == -sign * 211) {
            pi = p.children()[1];
          }
          else if (p.children()[1].pid() == sign * 4122 && p.children()[0].pid() == -sign * 211) {
            pi = p.children()[0];
          }
          else
            continue;
        }
        LorentzTransform boost = LorentzTransform::mkFrameTransformFromBeta(p.momentum().betaVec());
        Vector3 axis = boost.transform(pi.momentum()).p3().unit();
        double cosL = axis.dot(p.momentum().p3().unit());
        _h_cTheta->fill(cosL);
      }
    }


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

    /// @}


    /// @name Histograms
    /// @{
    Histo1DPtr _h_x, _h_cTheta;
    /// @}
  };


  RIVET_DECLARE_PLUGIN(CLEOII_1997_I424575);

}