Rivet analyses

title: BESIII_2022_I2122399

$pK^-$ mass distribution in $\Lambda_c^+\to pK^-e^+\nu_e$

Experiment: BESIII (BEPC)

Inspire ID: 2122399

Status: VALIDATED NOHEPDATA

Authors: - Peter Richardson

References: - arXiv: 2207.11483

Beams: * *

Beam energies: ANY

Run details: - Any process producing Lambda_c+

Measurement of the $pK^-$ mass distribution in $\Lambda_c^+\to pK^-e^+\nu_e$ by BES-III. N.B. The data were read from the paper and may not have been corrected for acceptance.

Source code:BESIII_2022_I2122399.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/DecayedParticles.hh"

include "Rivet/Projections/UnstableParticles.hh"

namespace Rivet {

/// @brief Lambda_c+ -> p K- e+ nu_e class BESIII_2022_I2122399 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(BESIII_2022_I2122399);


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

/// Book histograms and initialise projections before the run
void init() {
  // Initialise and register projections
  UnstableParticles ufs = UnstableParticles(Cuts::pid == 4122);
  declare(ufs, "UFS");
  DecayedParticles LambdaC(ufs);
  LambdaC.addStable(PID::PI0);
  LambdaC.addStable(PID::K0S);
  LambdaC.addStable(PID::ETA);
  LambdaC.addStable(PID::ETAPRIME);
  declare(LambdaC, "LambdaC");

  // Book histogram
  book(_h, 1, 1, 1);
}


/// Perform the per-event analysis
void analyze(const Event& event) {
  static const map<PdgId, unsigned int>& mode = {{-321, 1}, {2212, 1}, {-11, 1}, {12, 1}};
  DecayedParticles LambdaC = apply<DecayedParticles>(event, "LambdaC");
  // loop over particles
  for (unsigned int ix = 0; ix < LambdaC.decaying().size(); ++ix) {
    if (!LambdaC.modeMatches(ix, 4, mode)) continue;
    const Particle& Km = LambdaC.decayProducts()[ix].at(-321)[0];
    const Particle& pp = LambdaC.decayProducts()[ix].at(2212)[0];
    _h->fill((Km.momentum() + pp.momentum()).mass());
  }
}


/// Normalise histograms etc., after the run
void finalize() {
  normalize(_h, 1., false);
}

/// @}


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

};

RIVET_DECLARE_PLUGIN(BESIII_2022_I2122399);

} ```