Rivet analyses

title: ARGUS_1990_I283027

Anti-deuteron production in $\Upsilon$ decays

Experiment: ARGUS (DORIS)

Inspire ID: 283027

Status: VALIDATED

Authors: - Peter Richardson

References: - Phys.Lett. B236 (1990) 102-108

Beams: * *

Beam energies: ANY

Run details: - Upsilon(1S) decays (originally e+e- production)

Measurement of the anti-deuteron spectrum in $\Upsilon(1S)$ decays. The measurement was original an average of both $\Upsilon(1S)$ and $\Upsilon(2S)$ decays but the $\Upsilon(2S)$ sample is re-scaled to the $\Upsilon(1S)$.

Source code:ARGUS_1990_I283027.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/UnstableParticles.hh"

namespace Rivet {

/// @brief anti-deuteron spectrum in upslion decays class ARGUS_1990_I283027 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(ARGUS_1990_I283027);


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

/// Book histograms and initialise projections before the run
void init() {
  // Initialise and register projections
  declare(UnstableParticles(), "UFS");
  // histograms
  book(_h_p, 1, 1, 1);
  book(_w_ups, "TMP/w_ups");
}


/// Recursively walk the decay tree to find decay products of @a p
void findDecayProducts(Particle mother, Particles& deut) {
  // deuteron id code
  static const long id = -1000010020;
  for (const Particle& p : mother.children()) {
    if (p.pid() == id) {
      deut.push_back(p);
    }
    else if (!p.children().empty())
      findDecayProducts(p, deut);
  }
}


/// Perform the per-event analysis
void analyze(const Event& event) {
  for (const Particle& ups : apply<UnstableParticles>(event, "UFS").particles(Cuts::pid == 553)) {
    _w_ups->fill();
    Particles deut;
    findDecayProducts(ups, deut);
    if (deut.empty()) continue;
    LorentzTransform boost;
    if (ups.p3().mod() > 1 * MeV)
      boost = LorentzTransform::mkFrameTransformFromBeta(ups.momentum().betaVec());
    for (const Particle& p : deut) {
      double mom = boost.transform(p.momentum()).p3().mod();
      _h_p->fill(mom);
    }
  }
}


/// Normalise histograms etc., after the run
void finalize() {
  // direct upsilon decays, i.e. to gg gamma and ggg so need to renormalize
  // factor and values from arxiv:0612019
  double Bmumu = 0.0249, rhad = 3.56;
  double fact = 1. - (3. + rhad) * Bmumu;
  scale(_h_p, 1e5 / fact / *_w_ups);
}

/// @}


/// @name Histograms
/// @{
Histo1DPtr _h_p;
CounterPtr _w_ups;
/// @}

};

RIVET_DECLARE_PLUGIN(ARGUS_1990_I283027);

} ```