Rivet analyses

title: ARGUS_1994_I375418

Visible hadronic cross section near the $\Upsilon(1S)$, $\Upsilon(2S)$ and $\Upsilon(4S)$ resonances

Experiment: ARGUS (DORIS)

Inspire ID: 375418

Status: VALIDATED NOHEPDATA SINGLEWEIGHT

Authors: - Peter Richardson

References: - Z.Phys.C 65 (1995) 619-626

Beams: e- e+

Beam energies: ANY

Run details: - e+ e- to hadrons including the Upsilon resonances

Measurement of the visible hadronic cross section near the $\Upsilon(1S)$, $\Upsilon(2S)$ and $\Upsilon(4S)$ resonances. As the analyses requires the beam energy smearing described in the paper then central CMS energy should be specified using the ECENT (in GeV) option.

Source code:ARGUS_1994_I375418.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/ChargedFinalState.hh"

include "Rivet/Projections/FinalState.hh"

namespace Rivet {

/// @brief e+ e- > hadrons near Upsilon resonances class ARGUS_1994_I375418 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(ARGUS_1994_I375418);


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

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

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

  // Book histograms
  for (unsigned int ix = 0; ix < 3; ++ix) book(_sigma[ix], 1 + ix, 1, 1);
  _eCent = getOption<string>("ECENT", std::to_string(sqrtS() / MeV));
}


/// Perform the per-event analysis
void analyze(const Event& event) {
  if (apply<ChargedFinalState>(event, "CFS").particles().size() < 3) vetoEvent;
  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;
  }
  // mu+mu- + photons
  if (nCount[-13] == 1 and nCount[13] == 1 && ntotal == 2 + nCount[22]) {
    vetoEvent;
  }
  else if (nCount[-11] == 1 and nCount[11] == 1 && ntotal == 2 + nCount[22]) {
    vetoEvent;
  }
  else { // everything else
    _sigma[0]->fill(_eCent);
    _sigma[1]->fill(_eCent);
    double H0 = 0., H2 = 0;
    for (unsigned int ix = 0; ix < fs.particles().size(); ++ix) {
      double p1 = fs.particles()[ix].p3().mod();
      for (unsigned int iy = 0; iy < fs.particles().size(); ++iy) {
        double p2 = fs.particles()[iy].p3().mod();
        double cTheta = fs.particles()[ix].p3().dot(fs.particles()[iy].p3()) / p1 / p2;
        double pre = p1 * p2 / sqr(sqrtS());
        H0 += pre;
        H2 += 0.5 * pre * (3. * sqr(cTheta) - 1);
      }
    }
    if (H2 / H0 < 0.35) _sigma[2]->fill(_eCent);
  }
}


/// Normalise histograms etc., after the run
void finalize() {
  scale(_sigma, crossSection() / sumOfWeights() / nanobarn);
}

/// @}


/// @name Histograms
/// @{
BinnedHistoPtr<string> _sigma[3];
string _eCent;
/// @}

};

RIVET_DECLARE_PLUGIN(ARGUS_1994_I375418);

} ```