Rivet analyses

title: CLEO_2007_I732065

$\chi_{c1}\to \eta\pi^+\pi^-$, $K^+K^-\pi^0$ and $\pi^+K^-K^0_S$

Experiment: CLEO (CESR)

Inspire ID: 732065

Status: VALIDATED NOHEPDATA

Authors: - Peter Richardson

References: - Phys.Rev.D 75 (2007) 032002

Beams: * *

Beam energies: ANY

Run details: - Any process producing chi_c originally e+e-

Measurement of the mass distributions in the decays $\chi_{c1}\to \eta\pi^+\pi^-$, $K^+K^-\pi^0$ and $\pi^+K^-K^0_S$. The data were read from the plots in the paper and may not be corrected for efficiency or background.

Source code:CLEO_2007_I732065.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/DecayedParticles.hh"

include "Rivet/Projections/UnstableParticles.hh"

namespace Rivet {

/// @brief chi_c1 -> eta pi+pi- and KKpi class CLEO_2007_I732065 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(CLEO_2007_I732065);


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

/// Book histograms and initialise projections before the run
void init() {
  UnstableParticles ufs = UnstableParticles(Cuts::pid == 20443);
  declare(ufs, "UFS");
  DecayedParticles chi(ufs);
  chi.addStable(PID::PI0);
  chi.addStable(PID::K0S);
  chi.addStable(PID::ETA);
  declare(chi, "chi");
  for (unsigned int ix = 0; ix < 3; ++ix)
    for (unsigned int iy = 0; iy < 3; ++iy) book(_h[ix][iy], ix + 1, 1, iy + 1);
  book(_dalitz[0], "dalitz_1", 50, 0., 12., 50, 0., 9.);
  book(_dalitz[1], "dalitz_2", 50, 0., 10., 50, 0., 10.);
  book(_dalitz[2], "dalitz_3", 50, 0., 10., 50, 0., 10.);
}


/// Perform the per-event analysis
void analyze(const Event& event) {
  static const map<PdgId, unsigned int>& mode1 = {{221, 1}, {211, 1}, {-211, 1}};
  static const map<PdgId, unsigned int>& mode2 = {{321, 1}, {-321, 1}, {111, 1}};
  static const map<PdgId, unsigned int>& mode3 = {{-321, 1}, {310, 1}, {211, 1}};
  static const map<PdgId, unsigned int>& mode4 = {{321, 1}, {310, 1}, {-211, 1}};
  DecayedParticles chi = apply<DecayedParticles>(event, "chi");
  // loop over particles
  for (unsigned int ix = 0; ix < chi.decaying().size(); ++ix) {
    if (chi.modeMatches(ix, 3, mode1)) {
      const Particle& eta = chi.decayProducts()[ix].at(221)[0];
      const Particle& pim = chi.decayProducts()[ix].at(-211)[0];
      const Particle& pip = chi.decayProducts()[ix].at(211)[0];
      double m1 = (pip.momentum() + pim.momentum()).mass2();
      double m2 = (eta.momentum() + pip.momentum()).mass2();
      double m3 = (eta.momentum() + pim.momentum()).mass2();
      _dalitz[0]->fill(m2, m1);
      _h[0][0]->fill(m1);
      _h[0][1]->fill(m2);
      _h[0][2]->fill(m3);
    }
    else if (chi.modeMatches(ix, 3, mode2)) {
      const Particle& pi0 = chi.decayProducts()[ix].at(111)[0];
      const Particle& Km = chi.decayProducts()[ix].at(-321)[0];
      const Particle& Kp = chi.decayProducts()[ix].at(321)[0];
      double m1 = (pi0.momentum() + Km.momentum()).mass2();
      double m2 = (pi0.momentum() + Kp.momentum()).mass2();
      double m3 = (Kp.momentum() + Km.momentum()).mass2();
      _dalitz[1]->fill(m2, m1);
      _h[1][0]->fill(m1);
      _h[1][1]->fill(m2);
      _h[1][2]->fill(m3);
    }
    else {
      int sign = 1;
      if (chi.modeMatches(ix, 3, mode3)) {
        sign = 1;
      }
      else if (chi.modeMatches(ix, 3, mode4)) {
        sign = -1;
      }
      else
        continue;
      const Particle& KS0 = chi.decayProducts()[ix].at(310)[0];
      const Particle& Km = chi.decayProducts()[ix].at(-sign * 321)[0];
      const Particle& pip = chi.decayProducts()[ix].at(sign * 211)[0];
      double m1 = (pip.momentum() + Km.momentum()).mass2();
      double m2 = (pip.momentum() + KS0.momentum()).mass2();
      double m3 = (Km.momentum() + KS0.momentum()).mass2();
      _dalitz[2]->fill(m2, m1);
      _h[2][0]->fill(m1);
      _h[2][1]->fill(m2);
      _h[2][2]->fill(m3);
    }
  }
}


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

/// @}


/// @name Histograms
/// @{
Histo1DPtr _h[3][3];
Histo2DPtr _dalitz[3];
/// @}

};

RIVET_DECLARE_PLUGIN(CLEO_2007_I732065);

} ```