Rivet analyses

title: CLEO_2008_I787608

Mass distributions in $\chi_c\to\pi^+\pi^-\pi^0\pi^0$ and $K^\pm\pi^\mp K^0_S\pi^0$

Experiment: CLEO (CESR)

Inspire ID: 787608

Status: VALIDATED NOHEPDATA

Authors: - Peter Richardson

References: - Phys.Rev.D 78 (2008) 092004

Beams: * *

Beam energies: ANY

Run details: - Any process producing chi_c states

Measurement of the mass distributions in the decays $\chi_c\to\pi^+\pi^-\pi^0\pi^0$ and $K^\pm\pi^\mp K^0_S\pi^0$$. The data were read from the plots in the paper and may not be corrected for efficiency.

Source code:CLEO_2008_I787608.cc

```c++ // -- C++ --

include "Rivet/Analysis.hh"

include "Rivet/Projections/DecayedParticles.hh"

include "Rivet/Projections/UnstableParticles.hh"

namespace Rivet {

/// @briefchi_c -> pi+pi- 2pi0 and K pi K0 pi0 class CLEO_2008_I787608 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(CLEO_2008_I787608);


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

/// Book histograms and initialise projections before the run
void init() {
  UnstableParticles ufs = UnstableParticles(Cuts::pid == 10441 or Cuts::pid == 20443 or Cuts::pid == 445);
  declare(ufs, "UFS");
  DecayedParticles chi(ufs);
  chi.addStable(PID::PI0);
  chi.addStable(PID::K0S);
  chi.addStable(PID::ETA);
  chi.addStable(PID::ETAPRIME);
  declare(chi, "chi");
  unsigned int iK[3] = {4, 2, 5};
  for (unsigned int ix = 0; ix < 3; ++ix) {
    for (unsigned int iy = 0; iy < iK[ix]; ++iy) {
      // 4 pion
      if (iy < 2) book(_h_pi[ix][iy], 1 + ix, 1, 1 + iy);
      // 2 K 2 pi
      book(_h_K[ix][iy], 4 + ix, 1, 1 + iy);
    }
  }
}


/// Perform the per-event analysis
void analyze(const Event& event) {
  static const map<PdgId, unsigned int>& mode1 = {{211, 1}, {-211, 1}, {111, 2}};
  static const map<PdgId, unsigned int>& mode2 = {{321, 1}, {-211, 1}, {111, 1}, {310, 1}};
  static const map<PdgId, unsigned int>& mode3 = {{-321, 1}, {211, 1}, {111, 1}, {310, 1}};
  DecayedParticles chi = apply<DecayedParticles>(event, "chi");
  for (unsigned int ix = 0; ix < chi.decaying().size(); ++ix) {
    unsigned int iloc = 0;
    int sign = 1;
    if (chi.decaying()[ix].pid() == 20443)
      iloc = 1;
    else if (chi.decaying()[ix].pid() == 445)
      iloc = 2;
    if (chi.modeMatches(ix, 4, mode1)) {
      const Particle& pim = chi.decayProducts()[ix].at(-211)[0];
      const Particle& pip = chi.decayProducts()[ix].at(211)[0];
      const Particles& pi0 = chi.decayProducts()[ix].at(111);
      for (unsigned int ix = 0; ix < 2; ++ix) {
        _h_pi[iloc][0]->fill((pip.momentum() + pi0[ix].momentum()).mass());
        _h_pi[iloc][1]->fill((pim.momentum() + pi0[ix].momentum()).mass());
      }
      continue;
    }
    else if (chi.modeMatches(ix, 4, mode2)) {
      sign = 1;
    }
    else if (chi.modeMatches(ix, 4, mode3)) {
      sign = -1;
    }
    else
      continue;
    const Particle& pim = chi.decayProducts()[ix].at(-sign * 211)[0];
    const Particle& Kp = chi.decayProducts()[ix].at(sign * 321)[0];
    const Particle& pi0 = chi.decayProducts()[ix].at(111)[0];
    const Particle& K0 = chi.decayProducts()[ix].at(310)[0];
    _h_K[iloc][0]->fill((Kp.momentum() + pim.momentum()).mass());
    _h_K[iloc][1]->fill((pim.momentum() + pi0.momentum()).mass());
    if (_h_K[iloc][2]) _h_K[iloc][2]->fill((Kp.momentum() + pi0.momentum()).mass());
    if (_h_K[iloc][3]) _h_K[iloc][3]->fill((K0.momentum() + pim.momentum()).mass());
    if (_h_K[iloc][4]) _h_K[iloc][4]->fill((K0.momentum() + pi0.momentum()).mass());
  }
}


/// Normalise histograms etc., after the run
void finalize() {
  unsigned int iK[3] = {4, 2, 5};
  for (unsigned int ix = 0; ix < 3; ++ix) {
    for (unsigned int iy = 0; iy < iK[ix]; ++iy) {
      // 4 pion
      if (iy < 2) normalize(_h_pi[ix][iy], 1., false);
      // 2 K 2 pi
      normalize(_h_K[ix][iy], 1., false);
    }
  }
}

/// @}


/// @name Histograms
/// @{
Histo1DPtr _h_pi[3][2];
Histo1DPtr _h_K[3][5];
/// @}

};

RIVET_DECLARE_PLUGIN(CLEO_2008_I787608);

} ```