Rivet analyses

title: BES_1999_I508349

Charm cross sections and spectra at 4.03 and 4.14 GeV

Experiment: BES (BEPC)

Inspire ID: 508349

Status: VALIDATED

Authors: - Peter Richardson

References: - Phys.Rev. D62 (2000) 012002

Beams: e+ e-

Beam energies: (2.0, 2.0); (2.1, 2.1)GeV

Run details: - e+e- to hadrons.

Measurement of the total cvharm cross section, together with the $D^0$, $D^+$ rates and spectra at 4.03 and 4.14 GeV by the BES collaboration.

Source code:BES_1999_I508349.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/UnstableParticles.hh"

namespace Rivet {

/// @brief charm cross sections class BES_1999_I508349 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(BES_1999_I508349);


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

/// Book histograms and initialise projections before the run
void init() {
  declare(UnstableParticles(), "UFS");
  for (size_t ix = 0; ix < 4; ++ix) {
    book(_nD[ix], 1, 1, 1 + ix);
  }

  _edge = "4.03";
  for (double eVal : allowedEnergies()) {

    const string en = toString(round(eVal / MeV));
    if (isCompatibleWithSqrtS(eVal)) {
      _sqs = en;
      if (en == "4140"s) _edge = "4.14";
    }

    size_t ih = en == "4140"s;
    book(_h_D0[en], 2 + ih, 1, 1);
    book(_h_Dp[en], 2 + ih, 1, 2);
  }
  raiseBeamErrorIf(_sqs.empty());
}


/// Perform the per-event analysis
void analyze(const Event& event) {
  double nD0(0), nDp(0), nDs(0);
  for (const Particle& p :
       apply<UnstableParticles>(event, "UFS")
           .particles(Cuts::abspid == 411 or Cuts::abspid == 421 or Cuts::abspid == 431)) {
    if (p.abspid() == 421) {
      _h_D0[_sqs]->fill(p.mom().p3().mod());
      ++nD0;
    }
    else if (p.abspid() == 411) {
      _h_Dp[_sqs]->fill(p.mom().p3().mod());
      ++nDp;
    }
    else {
      ++nDs;
    }
  }
  _nD[0]->fill(_edge, 0.5 * nD0);
  _nD[1]->fill(_edge, 0.5 * nDp);
  _nD[2]->fill(_edge, 0.5 * nDs);
  _nD[3]->fill(_edge, 0.5 * (nD0 + nDp + nDs));
}


/// Normalise histograms etc., after the run
void finalize() {
  const double fact = crossSection() / sumOfWeights() / nanobarn;
  scale(_h_D0, 0.5 * fact);
  scale(_h_Dp, 0.5 * fact);
  scale(_nD, fact);
}

/// @}


/// @name Histograms
/// @{
BinnedHistoPtr<string> _nD[4];
map<string, Histo1DPtr> _h_D0, _h_Dp;
string _sqs = "", _edge = "";
/// @}

};

RIVET_DECLARE_PLUGIN(BES_1999_I508349);

} ```