Rivet analyses

title: FOCUS_2003_I618864

Mass distributions in the decays $\Xi_c^+\to\Sigma^+K^-\pi^+$ and $\Xi_c^+\to\Xi^-\pi^+\pi^+$

Experiment: FOCUS (Fermilab)

Inspire ID: 618864

Status: VALIDATED NOHEPDATA

Authors: - Peter Richardson

References: - Phys.Lett.B 571 (2003) 139-147

Beams: * *

Beam energies: ANY

Run details: - Any process producing Xic+ mesons

Measurement of the mass distributions in the decays $\Xi_c^+\to\Sigma^+K^-\pi^+$ and $\Xi_c^+\to\Xi^-\pi^+\pi^+$ by FOCUS. The data were read from the plots in the paper.

Source code:FOCUS_2003_I618864.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/DecayedParticles.hh"

include "Rivet/Projections/UnstableParticles.hh"

namespace Rivet {

/// @brief Xi_c+ -> Sigma+ K- pi+ and Xi- pi+ pi+ class FOCUS_2003_I618864 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(FOCUS_2003_I618864);


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

/// Book histograms and initialise projections before the run
void init() {
  // Initialise and register projections
  UnstableParticles ufs = UnstableParticles(Cuts::abspid == 4232);
  declare(ufs, "UFS");
  DecayedParticles XICP(ufs);
  XICP.addStable(PID::PI0);
  XICP.addStable(PID::K0S);
  XICP.addStable(PID::ETA);
  XICP.addStable(3222);
  XICP.addStable(-3222);
  XICP.addStable(3312);
  XICP.addStable(-3312);
  declare(XICP, "XICP");
  // histograms
  for (unsigned int ix = 0; ix < 2; ++ix) book(_h[ix], 1 + ix, 1, 1);
}


/// Perform the per-event analysis
void analyze(const Event& event) {
  static const map<PdgId, unsigned int>& mode1 = {{PID::KMINUS, 1}, {3222, 1}, {PID::PIPLUS, 1}};
  static const map<PdgId, unsigned int>& mode1CC = {{PID::KPLUS, 1}, {-3222, 1}, {PID::PIMINUS, 1}};
  static const map<PdgId, unsigned int>& mode2 = {{3312, 1}, {PID::PIPLUS, 2}};
  static const map<PdgId, unsigned int>& mode2CC = {{-3312, 1}, {PID::PIMINUS, 2}};
  DecayedParticles XICP = apply<DecayedParticles>(event, "XICP");
  // loop over particles
  for (unsigned int ix = 0; ix < XICP.decaying().size(); ++ix) {
    int sign = XICP.decaying()[ix].pid() / XICP.decaying()[ix].abspid();
    if ((sign == 1 && XICP.modeMatches(ix, 3, mode1))
        || (sign == -1 && XICP.modeMatches(ix, 3, mode1CC))) {
      const Particle& pip = XICP.decayProducts()[ix].at(sign * PID::PIPLUS)[0];
      const Particle& Km = XICP.decayProducts()[ix].at(sign * PID::KMINUS)[0];
      for (unsigned int ix = 0; ix < 2; ++ix) _h[0]->fill((pip.momentum() + Km.momentum()).mass());
    }
    else if ((sign == 1 && XICP.modeMatches(ix, 3, mode2))
             || (sign == -1 && XICP.modeMatches(ix, 3, mode2CC))) {
      const Particles& pip = XICP.decayProducts()[ix].at(sign * PID::PIPLUS);
      const Particle& xi = XICP.decayProducts()[ix].at(sign * 3312)[0];
      _h[1]->fill((pip[0].momentum() + xi.momentum()).mass());
      _h[1]->fill((pip[1].momentum() + xi.momentum()).mass());
    }
  }
}


/// Normalise histograms etc., after the run
void finalize() {
  for (unsigned int ix = 0; ix < 2; ++ix) normalize(_h[ix], 1., false);
}

/// @}


/// @name Histograms
/// @{
Histo1DPtr _h[2];
/// @}

};

RIVET_DECLARE_PLUGIN(FOCUS_2003_I618864);

} ```