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## Rivet analyses reference

### BABAR_2007_S6895344

Inclusive $\Lambda_c^+$ Production in $e^+e^-$ Annihilation at $\sqrt{s}=10.54$ GeV and in $\Upsilon(4S)$ Decays.
Experiment: BaBar (PEP-II)
Inspire ID: 725377
Status: VALIDATED
Authors:
• Peter Richardson
References:
• Phys.Rev. D75 (2007) 012003
• hep-ex/0609004
Beams: e+ e-
Beam energies: (3.5, 8.0); (3.5, 7.9) GeV
Run details:
• $e^+ e^-$ analysis on the $\Upsilon(4S)$ resonance, with CoM boosts of 8.0 GeV ($e^-$) and 3.5 GeV ($e^+$)

Measurements of the total production rates and momentum distributions of the charmed baryon $\Lambda_c^+$ in $e^+e^- \to$ hadrons at a centre-of-mass energy of 10.54 GeV and in $\Upsilon(4S)$ decays.

Source code: BABAR_2007_S6895344.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 // -*- C++ -*- #include "Rivet/Analysis.hh" #include "Rivet/Projections/Beam.hh" #include "Rivet/Projections/UnstableFinalState.hh" namespace Rivet { /// @brief BABAR Lambda_c from fragmentation /// @author Peter Richardson class BABAR_2007_S6895344 : public Analysis { public: BABAR_2007_S6895344() : Analysis("BABAR_2007_S6895344") { } void init() { declare(Beam(), "Beams"); declare(UnstableFinalState(), "UFS"); _histOff = bookHisto1D(1,1,1); _sigmaOff = bookHisto1D(2,1,1); _histOn = bookHisto1D(3,1,1); _sigmaOn = bookHisto1D(4,1,1); } void analyze(const Event& e) { const double weight = e.weight(); // Loop through unstable FS particles and look for charmed mesons/baryons const UnstableFinalState& ufs = apply(e, "UFS"); const Beam beamproj = apply(e, "Beams"); const ParticlePair& beams = beamproj.beams(); const FourMomentum mom_tot = beams.first.momentum() + beams.second.momentum(); const LorentzTransform cms_boost = LorentzTransform::mkFrameTransformFromBeta(mom_tot.betaVec()); const double s = sqr(beamproj.sqrtS()); const bool onresonance = fuzzyEquals(beamproj.sqrtS(), 10.58, 2E-3); // Particle masses from PDGlive (accessed online 16. Nov. 2009). foreach (const Particle& p, ufs.particles()) { // Only looking at Lambda_c if (p.abspid() != 4122) continue; MSG_DEBUG("Lambda_c found"); const double mH2 = 5.22780; // 2.28646^2 const double mom = FourMomentum(cms_boost.transform(p.momentum())).p(); const double xp = mom/sqrt(s/4.0 - mH2); if (onresonance) { _histOn ->fill(xp,weight); _sigmaOn ->fill(10.58, weight); } else { _histOff ->fill(xp,weight); _sigmaOff->fill(10.54, weight); } } } void finalize() { scale(_sigmaOn , 1./sumOfWeights()); scale(_sigmaOff, 1./sumOfWeights()); scale(_histOn , 1./sumOfWeights()); scale(_histOff , 1./sumOfWeights()); } private: //@{ // Histograms for the continuum cross sections Histo1DPtr _sigmaOn ; Histo1DPtr _sigmaOff; Histo1DPtr _histOn ; Histo1DPtr _histOff ; //@} }; // The hook for the plugin system DECLARE_RIVET_PLUGIN(BABAR_2007_S6895344); }