Rivet analyses

Rate and spectra for the production of Σc(2800)

Experiment: BELLE (KEKB)

Inspire ID: 668024

Status: VALIDATED

Authors: - Peter Richardson

References: - Phys.Rev.Lett. 94 (2005) 122002

Beams: e+ e-

Beam energies: (5.3, 5.3)GeV

Run details: - e+e- to hadrons

Measurement of the rate and scaled momentum spectra for the production of Σc(2800)0, Σc(2800)+ and Σc(2800)++ baryons by BELLE.

Source code:BELLE_2004_I668024.cc

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

namespace Rivet {


  /// @brief Sigma_c(2800) rate and spectra
  class BELLE_2004_I668024 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(BELLE_2004_I668024);


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

    /// Book histograms and initialise projections before the run
    void init() {
      // Initialise and register projections
      declare(UnstableParticles(), "UFS");
      // Book histograms
      for (unsigned int ix = 0; ix < 3; ++ix) {
        book(_r[ix], 1, 1, 1 + ix);
        book(_h[ix], 2, 1, 1 + ix);
      }
    }


    /// Perform the per-event analysis
    void analyze(const Event& event) {
      const UnstableParticles& ufs = apply<UnstableParticles>(event, "UFS");

      for (const Particle& p : ufs.particles()) {
        const Vector3 mom3 = p.p3();
        double pp = mom3.mod();
        double xp = pp / sqrt(0.25 * sqr(sqrtS()) - sqr(p.mass()));
        int id = abs(p.pid());
        if (id == _sid + 110 && isDecay(p, {4122, -211})) {
          _h[0]->fill(xp);
          _r[0]->fill("10.52"s);
        }
        else if (id == _sid + 210 && isDecay(p, {4122, 111})) {
          _h[1]->fill(xp);
          _r[1]->fill("10.52"s);
        }
        else if (id == _sid + 220 && isDecay(p, {4122, 211})) {
          _h[2]->fill(xp);
          _r[2]->fill("10.52"s);
        }
      }
    }

    // Check for explicit decay into pdgids
    bool isDecay(const Particle& mother, vector<int> ids) {
      if (mother.pid() < 0) {
        for (unsigned int ix = 0; ix < ids.size(); ++ix) ids[ix] *= -1;
      }
      // Trivial check to ignore any other decays but the one in question modulo photons
      const Particles children = mother.children(Cuts::pid != PID::PHOTON);
      if (children.size() != ids.size()) return false;
      // Check for the explicit decay
      return all(ids, [&](int i) { return count(children, hasPID(i)) == 1; });
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      for (unsigned int ix = 0; ix < 3; ++ix) {
        normalize(_h[ix]);
        scale(_r[ix], crossSection() / picobarn / sumOfWeights());
      }
    }

    /// @}


    /// @name Histograms
    /// @{
    Histo1DPtr _h[3];
    BinnedHistoPtr<string> _r[3];
    static const int _sid = 14002;
    /// @}
  };


  RIVET_DECLARE_PLUGIN(BELLE_2004_I668024);

}