Rivet analyses

title: BELLE_2004_I668024

Rate and spectra for the production of $\Sigma_c(2800)$

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 $\Sigma_c(2800)^0$, $\Sigma_c(2800)^+$ and $\Sigma_c(2800)^{++}$ baryons by BELLE.

Source code:BELLE_2004_I668024.cc

```c++ // -- 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);

} ```