Rivet analyses

title: CLEO_2007_I728872

Spectrum of $\phi$ mesons in $\Upsilon(4S)$ and $\Upsilon(5S)$ decays

Experiment: CLEO (CESR)

Inspire ID: 728872

Status: VALIDATED

Authors: - Peter Richardson

References: - Phys.Rev. D75 (2007) 012002

Beams: * *

Beam energies: ANY

Run details: - Any process producing $\Upsilon(4S)$ or $\Upsilon(5S)$, original $e^+e^-$

Measurement of the $\phi$ meson spectrum in $\Upsilon(4S)$ and $\Upsilon(5S)$ decays by CLEO, only the spectra are included not the conclusions on $B_s$ production drawn from them.

Source code:CLEO_2007_I728872.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/UnstableParticles.hh"

namespace Rivet {

/// @brief phi spectrum at Upsilon 4 and 5s class CLEO_2007_I728872 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(CLEO_2007_I728872);


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

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

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

  // Book histograms
  book(_h_4S, 1, 1, 5);
  book(_h_5S, 2, 1, 5);
  book(_c_4S, "/TMP/N4S");
  book(_c_5S, "/TMP/N5S");
}

void findDecayProducts(const Particle& p, Particles& phi) {
  for (const Particle& child : p.children()) {
    if (child.pid() == 333)
      phi.push_back(child);
    else if (!child.children().empty())
      findDecayProducts(child, phi);
  }
}

/// Perform the per-event analysis
void analyze(const Event& event) {
  // Find the Upsilons among the unstables
  const UnstableParticles& ufs = apply<UnstableParticles>(event, "UFS");
  Particles upsilons = ufs.particles(Cuts::pid == 300553 || Cuts::pid == 400553 || Cuts::pid == 9000553);
  for (const Particle& ups : upsilons) {
    LorentzTransform cms_boost;
    if (ups.p3().mod() > 1 * MeV)
      cms_boost = LorentzTransform::mkFrameTransformFromBeta(ups.momentum().betaVec());
    Particles phis;
    findDecayProducts(ups, phis);

    if (ups.pid() == 300553)
      _c_4S->fill();
    else
      _c_5S->fill();

    for (const Particle& phi : phis) {
      FourMomentum p2 = cms_boost.transform(phi.momentum());
      double x = 2. * p2.p3().mod() / ups.mass();
      if (ups.pid() == 300553)
        _h_4S->fill(x);
      else
        _h_5S->fill(x);
    }
  }
}


/// Normalise histograms etc., after the run
void finalize() {
  if (_h_4S->effNumEntries() != 0) scale(_h_4S, 100. / *_c_4S);
  if (_h_5S->effNumEntries() != 0) scale(_h_5S, 100. / *_c_5S);
}

/// @}


/// @name Histograms
/// @{
Histo1DPtr _h_4S, _h_5S;
CounterPtr _c_4S, _c_5S;
/// @}

};

RIVET_DECLARE_PLUGIN(CLEO_2007_I728872);

} ```