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## Rivet analyses reference

### BABAR_2004_I632399

$\phi$ momentum spectra in $\Upsilon(4S)$ decays
Experiment: BABAR (PEP-II)
Inspire ID: 632399
Status: VALIDATED
Authors:
• Peter Richardson
No references listed
Beams: * *
Beam energies: ANY
Run details:
• Any process producing Upsilon(4S) originally e+e-

Measurement of the momentum spectrum of $\phi$ mesons produced in $B$ decays at the $\Upsilon(4S)$ resonance.

Source code: BABAR_2004_I632399.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 // -*- C++ -*- #include "Rivet/Analysis.hh" #include "Rivet/Projections/UnstableParticles.hh" namespace Rivet { /// @brief phi spectrum at 4S class BABAR_2004_I632399 : public Analysis { public: /// Constructor DEFAULT_RIVET_ANALYSIS_CTOR(BABAR_2004_I632399); /// @name Analysis methods ///@{ /// Book histograms and initialise projections before the run void init() { // Initialise and register projections declare(UnstableParticles(), "UFS"); // Book histograms book(_b_phi, 1, 1, 1); book(_h_phi, 2, 1, 1); book(_c_4S, "/TMP/N4S"); } 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(event, "UFS"); Particles upsilons = ufs.particles(Cuts::pid==300553); 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); _c_4S->fill(); for(const Particle & phi : phis) { FourMomentum p2 = cms_boost.transform(phi.momentum()); _h_phi->fill(p2.p3().mod()); _b_phi->fill(0.5); } } } /// Normalise histograms etc., after the run void finalize() { if(_c_4S->effNumEntries()!=0) { scale(_h_phi , 0.5/ *_c_4S); scale(_b_phi , 50./ *_c_4S ); } } ///@} /// @name Histograms ///@{ Histo1DPtr _h_phi,_b_phi; CounterPtr _c_4S; ///@} }; DECLARE_RIVET_PLUGIN(BABAR_2004_I632399); }