Rivet analyses

title: BESIII_2022_I2038523

Hadronic mass in $D^+_s\to \pi^0\pi^0 e^+\nu_e$

Experiment: BESIII (BEPC)

Inspire ID: 2038523

Status: VALIDATED NOHEPDATA

Authors: - Peter Richardson

References: - Phys.Rev.D 105 (2022) 3, L031101

Beams: * *

Beam energies: ANY

Run details: - Any process producing Ds+

Measurement of the hadronic mass in $D^+_s\to \pi^0\pi^0 e^+\nu_e$ by BES-III. N.B. the plots where read from the paper and may not have been corrected for acceptance.

Source code:BESIII_2022_I2038523.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/DecayedParticles.hh"

include "Rivet/Projections/UnstableParticles.hh"

namespace Rivet {

/// @brief D_s+ -> pi0 pi0 e+ nu_e class BESIII_2022_I2038523 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(BESIII_2022_I2038523);


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

/// Book histograms and initialise projections before the run
void init() {
  UnstableParticles ufs = UnstableParticles(Cuts::pid == 431);
  declare(ufs, "UFS");
  DecayedParticles DD(ufs);
  DD.addStable(PID::PI0);
  DD.addStable(PID::K0S);
  DD.addStable(PID::ETA);
  DD.addStable(PID::ETAPRIME);
  declare(DD, "DD");
  book(_h, 1, 1, 1);
}


/// Perform the per-event analysis
void analyze(const Event& event) {
  static const map<PdgId, unsigned int>& mode = {{111, 2}, {-11, 1}, {12, 1}};
  DecayedParticles DD = apply<DecayedParticles>(event, "DD");
  // loop over particles
  for (unsigned int ix = 0; ix < DD.decaying().size(); ++ix) {
    if (!DD.modeMatches(ix, 4, mode)) continue;
    const Particles& pi0 = DD.decayProducts()[ix].at(111);
    _h->fill((pi0[0].momentum() + pi0[1].momentum()).mass());
  }
}


/// Normalise histograms etc., after the run
void finalize() {
  normalize(_h);
}

/// @}


/// @name Histograms
/// @{
Histo1DPtr _h;
/// @}

};

RIVET_DECLARE_PLUGIN(BESIII_2022_I2038523);

} ```