Rivet analyses

title: BELLE_2017_I1606201

Baryon spectra in $e^+e^-$ collisions at 10.52 GeV

Experiment: BELLE (KEKB)

Inspire ID: 1606201

Status: VALIDATED

Authors: - Peter Richardson

References: - Phys.Rev. D97 (2018) no.7, 072005

Beams: e- e+

Beam energies: (5.3, 5.3)GeV

Run details: - e+ e- to hadrons and e+ e-

Measurement of spectra for hyperon and charm baryon production in $e^+e^-$ collisions at 10.52 GeV by BELLE. The spectra for $\Lambda^0$, $\Sigma^0$, $\Sigma^{+}$, $\Lambda^0(1520)$, $\Xi^-$, $\Omega^-$ and $\Xi^{0}$ hyperons are measured. The spectra for the $\Lambda_c^+$, $\Lambda_c(2595)^+$, $\Lambda_c(2625)^+$, $\Sigma_c(2455)^0$, $\Sigma_c(2520)^0$, $\Omega_c^0$ and $\Xi_c^0$ charm baryons are also measured.

Source code:BELLE_2017_I1606201.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/UnstableParticles.hh"

namespace Rivet {

/// @brief baryon rates and spectra class BELLE_2017_I1606201 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(BELLE_2017_I1606201);


/// @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 = 1; ix < 16; ++ix) {
    book(_h[ix], ix, 1, 1);
    book(_r[ix], 16, 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 == 3122) {
      _h[1]->fill(xp);
      _r[1]->fill(0.5);
    }
    else if (id == 3212) {
      _h[2]->fill(xp);
      _r[2]->fill(0.5);
    }
    else if (id == 3224) {
      _h[3]->fill(xp);
      _r[3]->fill(0.5);
    }
    else if (id == 102134) {
      _h[4]->fill(xp);
      _r[4]->fill(0.5);
    }
    else if (id == 3312) {
      _h[5]->fill(xp);
      _r[5]->fill(0.5);
    }
    else if (id == 3334) {
      _h[6]->fill(xp);
      _r[6]->fill(0.5);
    }
    else if (id == 3324) {
      _h[7]->fill(xp);
      _r[7]->fill(0.5);
    }
    else if (id == 4122) {
      _h[8]->fill(xp);
      _r[8]->fill(0.5);
    }
    else if (id == 102142) {
      _h[9]->fill(xp);
      _r[9]->fill(0.5);
    }
    else if (id == 102144) {
      _h[10]->fill(xp);
      _r[10]->fill(0.5);
    }
    else if (id == 4112) {
      _h[11]->fill(xp);
      _r[11]->fill(0.5);
    }
    else if (id == 4114) {
      _h[12]->fill(xp);
      _r[12]->fill(0.5);
    }
    else if (id == 4332) {
      if (isDecay(p, {3334, -211})) {
        _h[13]->fill(xp);
        _r[13]->fill(0.5);
      }
    }
    else if (id == 4132) {
      if (isDecay(p, {3312, 211})) {
        _h[14]->fill(xp);
        _r[14]->fill(0.5);
      }
      else if (isDecay(p, {3334, 321})) {
        _h[15]->fill(xp);
        _r[15]->fill(0.5);
      }
    }
  }
}

// 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() {
  // norm to cross section
  for (unsigned int ix = 1; ix < 16; ++ix) {
    if (ix <= 4 || (ix >= 8 && ix <= 12))
      scale(_h[ix], crossSection() / nanobarn / sumOfWeights());
    else
      scale(_h[ix], crossSection() / picobarn / sumOfWeights());
    scale(_r[ix], crossSection() / picobarn / sumOfWeights());
  }
}

/// @}


/// @name Histograms
/// @{
Histo1DPtr _h[16], _r[16];
/// @}

};

RIVET_DECLARE_PLUGIN(BELLE_2017_I1606201);

} ```