Rivet analyses

title: JADE_1984_I203145

Spectra of $\rho^0$ and $K^{*\pm}$ in $e^+e^-$ collisions at 35 GeV

Experiment: JADE (PETRA)

Inspire ID: 203145

Status: VALIDATED

Authors: - Peter Richardson

References: - Phys.Lett. B145 (1984) 441-447, 1984

Beams: e+ e-

Beam energies: (17.5, 17.5)GeV

Run details: - e+ e- to hadrons

Measurement of the $\rho^0$ and $K^{*\pm}$ spectra in $e^+e^-$ collisions for centre-of-mass energy 35 GeV by the JADE experiment at Petra.

Source code:JADE_1984_I203145.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/Beam.hh"

include "Rivet/Projections/UnstableParticles.hh"

namespace Rivet {

/// @brief rho0 and K*+/- spectra at 35 GeV class JADE_1984_I203145 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(JADE_1984_I203145);


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

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

  // Initialise and register projections
  declare(Beam(), "Beams");
  declare(UnstableParticles(), "UFS");

  // Book histograms
  book(_h_rho, 2, 1, 1);
  book(_h_kstar, 3, 1, 1);
}


/// Perform the per-event analysis
void analyze(const Event& event) {

  // Get beams and average beam momentum
  const ParticlePair& beams = apply<Beam>(event, "Beams").beams();
  const double meanBeamMom = (beams.first.p3().mod() + beams.second.p3().mod()) / 2.0;
  MSG_DEBUG("Avg beam momentum = " << meanBeamMom);

  for (const Particle& p :
       apply<UnstableParticles>(event, "UFS").particles(Cuts::abspid == 323 or Cuts::pid == 113)) {
    double xE = p.E() / meanBeamMom;
    double modp = p.p3().mod();
    double beta = modp / p.E();
    if (p.pid() == 113) {
      _h_rho->fill(xE, 1. / beta);
    }
    else {
      _h_kstar->fill(xE, 1. / beta);
    }
  }
}


/// Normalise histograms etc., after the run
void finalize() {

  scale(_h_rho, sqr(sqrtS()) * crossSection() / nanobarn / sumOfWeights());
  scale(_h_kstar, sqr(sqrtS()) * crossSection() / nanobarn / sumOfWeights());
}

/// @}


/// @name Histograms
/// @{
Histo1DPtr _h_rho, _h_kstar;
/// @}

};

RIVET_DECLARE_PLUGIN(JADE_1984_I203145);

} ```