Rivet analyses

title: DELPHI_1999_I482816

Measurement of inclusive $\rho^0$, $f_0(980)$, $f_2(1270)$, $K^{*0}_2(1430)$ and $f'_2(1525)$ production in $Z^0$ decays

Experiment: DELPHI (LEP 1)

Inspire ID: 482816

Status: VALIDATED

Authors: - Peter Richardson

References: - Phys.Lett.B449:364-382,1999

Beams: e+ e-

Beam energies: (45.6, 45.6)GeV

Run details: - Hadronic Z decay events generated on the Z pole ($\sqrt{s} = 91.2$ GeV)

DELPHI results for the production of $\rho^0$, $f_0(980)$, $f_2(1270)$, $K^{*0}_2(1430)$ and $f'_2(1525)$ in $Z^0$ decays. Only the identified particle spectra for $\rho^0$, $f_0(980)$ and $f_2(1270)$ are implemented.

Source code:DELPHI_1999_I482816.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/Beam.hh"

include "Rivet/Projections/ChargedFinalState.hh"

include "Rivet/Projections/FinalState.hh"

include "Rivet/Projections/UnstableParticles.hh"

namespace Rivet {

/// @brief DELPHI rho,f_0 and f_2 fragmentation function paper /// /// @author Peter Richardson class DELPHI_1999_I482816 : public Analysis { public:

RIVET_DEFAULT_ANALYSIS_CTOR(DELPHI_1999_I482816);


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

void init() {
  declare(Beam(), "Beams");
  declare(ChargedFinalState(), "FS");
  declare(UnstableParticles(), "UFS");
  book(_histXpRho, 1, 1, 1);
  book(_histXpf0, 1, 1, 2);
  book(_histXpf2, 1, 1, 3);
}


void analyze(const Event& e) {
  // First, veto on leptonic events by requiring at least 4 charged FS particles
  const FinalState& fs = apply<FinalState>(e, "FS");
  const size_t numParticles = fs.particles().size();

  // Even if we only generate hadronic events, we still need a cut on numCharged >= 2.
  if (numParticles < 2) {
    MSG_DEBUG("Failed leptonic event cut");
    vetoEvent;
  }
  MSG_DEBUG("Passed leptonic event cut");

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

  // Final state of unstable particles to get particle spectra
  const UnstableParticles& ufs = apply<UnstableParticles>(e, "UFS");

  for (const Particle& p : ufs.particles()) {
    const int id = p.abspid();
    double xp = p.p3().mod() / meanBeamMom;
    switch (id) {
      case 9010221: _histXpf0->fill(xp); break;
      case 225: _histXpf2->fill(xp); break;
      case 113: _histXpRho->fill(xp); break;
    }
  }
}


/// Finalize
void finalize() {
  scale(_histXpf0, 1. / sumOfWeights());
  scale(_histXpf2, 1. / sumOfWeights());
  scale(_histXpRho, 1. / sumOfWeights());
}

/// @}

private:

Histo1DPtr _histXpf0;
Histo1DPtr _histXpf2;
Histo1DPtr _histXpRho;

};

RIVET_DECLARE_ALIASED_PLUGIN(DELPHI_1999_I482816, DELPHI_1999_S3960137);

} ```

Aliases: - DELPHI_1999_S3960137