Rivet analyses

title: BELLE_2024_I2775022

Cross section for $e^+e^-\to$ $\pi^+\pi^-\pi^0$ between 0.62 and 3.5 GeV

Experiment: BELLE (KEKB)

Inspire ID: 2775022

Status: VALIDATED

Authors: - Peter Richardson

References: - Phys.Rev.D 110 (2024) 11, 112005 - arXiv: 2404.04915

Beams: e+ e-

Beam energies: ANY

Run details: - e+e- to hadrons, pi0 stable

Measurement of the cross section for $e^+e^-\to \pi^+\pi^-\pi^0$ by BaBar using radiative return for energies between 0.62 and 3.5 GeV. The contribution of the $J/\psi$ has been subtracted.

Source code:BELLE_2024_I2775022.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/FinalState.hh"

namespace Rivet {

/// @brief e+e- -> pi+pi-pi0 class BELLE_2024_I2775022 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(BELLE_2024_I2775022);


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

/// Book histograms and initialise projections before the run
void init() {

  // Initialise and register projections
  declare(FinalState(), "FS");

  for (unsigned int ix = 0; ix < 2; ++ix)
    book(_h[ix], "TMP/num_" + toString(ix + 1), refData(1 + ix, 1, 3));
}


/// Perform the per-event analysis
void analyze(const Event& event) {
  const FinalState& fs = apply<FinalState>(event, "FS");

  map<long, int> nCount;
  int ntotal(0);
  for (const Particle& p : fs.particles()) {
    nCount[p.pid()] += 1;
    ++ntotal;
  }
  if (ntotal != 3) vetoEvent;
  if (nCount[-211] == 1 && nCount[211] == 1 && nCount[111] == 1) {
    _h[0]->fill(sqrtS());
    _h[1]->fill(sqrtS());
  }
}


/// Normalise histograms etc., after the run
void finalize() {
  scale(_h, crossSection() / sumOfWeights() / nanobarn);
  for (unsigned int ix = 0; ix < 2; ++ix) {
    Estimate1DPtr tmp;
    book(tmp, 1 + ix, 1, 3);
    barchart(_h[ix], tmp);
  }
}

/// @}


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

};

RIVET_DECLARE_PLUGIN(BELLE_2024_I2775022);

} ```