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## Rivet analyses reference

### CLEOII_2002_I601701

Spectra of $\eta^\prime$ mesons in $\Upsilon(1S)$ decays
Experiment: CLEO-II (CESR)
Inspire ID: 601701
Status: VALIDATED
Authors:
• Peter Richardson
References:
• Phys.Rev. D67 (2003) 052003
Beams: * *
Beam energies: ANY
Run details:
• Any process producing Upslion 1S, original $e^+ e^-$

Measurement of the inclusive production of the $\eta^\prime$ mesons in $\Upsilon(1S)$ decays by the CLEO-II experiment. In principle this measurement is superseeded, however the newer result (CLEOIII_2006_I728679) did not include numerical values which were read from the plots and therefore we keep this measurement.

Source code: CLEOII_2002_I601701.cc
 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 // -*- C++ -*- #include "Rivet/Analysis.hh" #include "Rivet/Projections/UnstableParticles.hh" namespace Rivet { /// @brief eta' production in Upsilon(1S) decays class CLEOII_2002_I601701 : public Analysis { public: /// Constructor DEFAULT_RIVET_ANALYSIS_CTOR(CLEOII_2002_I601701); /// @name Analysis methods //@{ /// Book histograms and initialise projections before the run void init() { declare(UnstableParticles(), "UFS"); book(_hist , 1, 1, 3); book(_mult,"TMP/mult"); book(_weightSum,"TMP/weightSum"); } /// Recursively walk the decay tree to find decay products of @a p void findDecayProducts(Particle mother, Particles& unstable) { for(const Particle & p: mother.children()) { const int id = abs(p.pid()); if ( id == 331 ) { unstable.push_back(p); } else if(!p.children().empty()) findDecayProducts(p, unstable); } } /// Perform the per-event analysis void analyze(const Event& event) { // find the Upsilon(1S) mesons const UnstableParticles& ufs = apply(event, "UFS"); Particles upsilons = ufs.particles(Cuts::pid==553); if(upsilons.empty()) vetoEvent; // loop over them for (const Particle& ups : upsilons) { _weightSum->fill(); Particles unstable; // Find the decay products we want findDecayProducts(ups,unstable); LorentzTransform cms_boost; if (ups.p3().mod() > 0.001) cms_boost = LorentzTransform::mkFrameTransformFromBeta(ups.momentum().betaVec()); double mass = ups.mass(); _mult->fill(unstable.size()); // fill the spectrum for( const Particle & p : unstable) { FourMomentum p2 = cms_boost.transform(p.momentum()); double xp = 2.*p2.E()/mass; _hist->fill(xp); } } } /// Normalise histograms etc., after the run void finalize() { // spectrum if (_weightSum->val() > 0.) scale(_hist, 1. / *_weightSum); // BR Scatter2DPtr scatter; book(scatter,2, 1, 3, true); scale(_mult,1./ *_weightSum); scatter->point(0).setY(_mult->val(),_mult->err()); } //@} /// @name Histograms //@{ Histo1DPtr _hist; CounterPtr _mult; CounterPtr _weightSum; //@} }; DECLARE_RIVET_PLUGIN(CLEOII_2002_I601701); }