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CLEOII_1994_I381696

Spectrum for $\Lambda_c^+(2595)$ and $\Lambda_c^+(2625)$ production at 10.58 GeV
Experiment: CLEOII (CESR)
Inspire ID: 381696
Status: VALIDATED
Authors:
  • Peter Richardson
References:
  • Phys.Rev.Lett. 74 (1995) 3331-3335
Beams: e+ e-
Beam energies: (5.3, 5.3) GeV
Run details:
  • e+e- to hadrons

Spectrum for $\Lambda_c^+(2595)$ and $\Lambda_c^+(2625)$ production at 10.58 GeV measured by CLEOII.

Source code: CLEOII_1994_I381696.cc
  1// -*- C++ -*-
  2#include "Rivet/Analysis.hh"
  3#include "Rivet/Projections/Beam.hh"
  4#include "Rivet/Projections/UnstableParticles.hh"
  5
  6namespace Rivet {
  7
  8
  9  /// @brief Excited Lambda_c spectra
 10  class CLEOII_1994_I381696 : public Analysis {
 11  public:
 12
 13    /// Constructor
 14    RIVET_DEFAULT_ANALYSIS_CTOR(CLEOII_1994_I381696);
 15
 16
 17    /// @name Analysis methods
 18    ///@{
 19
 20    /// Book histograms and initialise projections before the run
 21    void init() {
 22      // projections
 23      declare(Beam(), "Beams");
 24      declare(UnstableParticles(), "UFS");
 25      // book histos
 26      book(_h_2595,5,1,1);
 27      book(_h_2625,6,1,1);
 28      book(_r_2595,4,1,1);
 29      book(_r_2625,4,1,2);
 30      book(_c_lam,"TMP/c_lam");
 31    }
 32
 33   
 34
 35    void findDecayProducts(const Particle& mother, unsigned int & npip,
 36			   unsigned int & npim, unsigned int & nlam) {
 37      for(const Particle & p : mother.children()) {
 38	if(p.abspid()  == 4122) ++nlam;
 39	else if(p.pid()==  211) ++npip;
 40	else if(p.pid()== -211) ++npim;
 41	else if(!p.children().empty())
 42	  findDecayProducts(p,npip,npim,nlam);
 43      }
 44    }
 45
 46    /// Perform the per-event analysis
 47    void analyze(const Event& event) {
 48      static const int id2595 = 14122;
 49      static const int id2625 = 4124;
 50      // Get beams and average beam momentum
 51      const ParticlePair& beams = apply<Beam>(event, "Beams").beams();
 52      const double Emax = ( beams.first.p3().mod() + beams.second.p3().mod() ) / 2.0;
 53      const UnstableParticles& ufs = apply<UnstableParticles>(event, "UFS");
 54      for (const Particle& p : ufs.particles(Cuts::abspid==id2595 or
 55					     Cuts::abspid==id2625)) {
 56	unsigned int nlam(0),npip(0),npim(0);
 57	findDecayProducts(p,npip,npim,nlam);
 58	bool isDecay = npip==1 && npim==1 && nlam==1;
 59	// spectrum
 60	if(p.abspid()==id2595) {
 61	  double Pmax = sqrt(sqr(Emax)-sqr(2.595));
 62	  double xp = p.momentum().p3().mod()/Pmax;
 63	  _h_2595->fill(xp);
 64	  if(isDecay) _r_2595->fill(10.55);
 65	}
 66	else {
 67	  double Pmax = sqrt(sqr(Emax)-sqr(2.625));
 68	  double xp = p.momentum().p3().mod()/Pmax;
 69	  _h_2625->fill(xp);
 70	  if(isDecay) _r_2625->fill(10.55);
 71	}
 72      }
 73      unsigned int nlam = ufs.particles(Cuts::abspid==4122).size();
 74      _c_lam->fill(nlam);
 75    }
 76
 77
 78    /// Normalise histograms etc., after the run
 79    void finalize() {
 80      normalize(_h_2595);
 81      normalize(_h_2625);
 82      scale(_r_2595, 0.06/ *_c_lam);
 83      scale(_r_2625, 0.06/ *_c_lam);
 84    }
 85
 86    ///@}
 87
 88
 89    /// @name Histograms
 90    ///@{
 91    Histo1DPtr _h_2595,_h_2625;
 92    Histo1DPtr _r_2595,_r_2625;
 93    CounterPtr _c_lam;
 94    ///@}
 95
 96
 97  };
 98
 99
100  RIVET_DECLARE_PLUGIN(CLEOII_1994_I381696);
101
102}