Rivet analyses reference

CLEOC_2008_I784516

Pion mass distribution in $\psi(2S)\to\pi\pi J/\psi$
Experiment: CLEOC (CESR)
Inspire ID: 784516
Status: VALIDATED NOHEPDATA
Authors:

Peter Richardson

References:

Phys.Rev.D 78 (2008) 011102

Beams: * *
Beam energies: ANY
Run details:

Any process producing psi(2S)

Measurement of the mass distribution in $\psi(2S)\to\pi^+\pi^-J/\psi$ and $\pi^0\pi^0J/\psi$ decays by CLEO. THe data were read from the plots in the paper and may not be corrected for efficiency/acceptance.

Source code: CLEOC_2008_I784516.cc

 1// -*- C++ -*-
 2#include "Rivet/Analysis.hh"
 3#include "Rivet/Projections/UnstableParticles.hh"
 4#include "Rivet/Projections/DecayedParticles.hh"
 5
 6namespace Rivet {
 7
 8
 9  /// @brief  psi(2S) -> J/Psi pi pi
10  class CLEOC_2008_I784516 : public Analysis {
11  public:
12
13    /// Constructor
14    RIVET_DEFAULT_ANALYSIS_CTOR(CLEOC_2008_I784516);
15
16
17    /// @name Analysis methods
18    /// @{
19
20    /// Book histograms and initialise projections before the run
21    void init() {
22      // Initialise and register projections
23      UnstableParticles ufs = UnstableParticles(Cuts::pid==100443);
24      declare(ufs, "UFS");
25      DecayedParticles psi(ufs);
26      psi.addStable(PID::PI0);
27      psi.addStable(PID::JPSI);
28      declare(psi, "psi");
29      for(unsigned int ix=0;ix<2;++ix)
30	book(_h[ix],1,1,1+ix);
31    }
32
33
34    /// Perform the per-event analysis
35    void analyze(const Event& event) {
36      static const map<PdgId,unsigned int> & mode1 = { { 211,1}, {-211,1}, { 443,1} };
37      static const map<PdgId,unsigned int> & mode2 = { { 111,2}          , { 443,1} };
38      DecayedParticles psi = apply<DecayedParticles>(event, "psi");
39      // loop over particles
40      for(unsigned int ix=0;ix<psi.decaying().size();++ix) {
41	if(psi.modeMatches(ix,3,mode1)) {
42	  const Particle & pip = psi.decayProducts()[ix].at( 211)[0];
43	  const Particle & pim = psi.decayProducts()[ix].at(-211)[0];
44	  _h[0]->fill((pip.momentum()+pim.momentum()).mass());
45	}
46	else if(psi.modeMatches(ix,3,mode2)) {
47	  const Particles & pi0 = psi.decayProducts()[ix].at( 111);
48	  _h[1]->fill((pi0[0].momentum()+pi0[1].momentum()).mass());
49	}
50      }
51    }
52
53
54    /// Normalise histograms etc., after the run
55    void finalize() {
56      for(unsigned int ix=0;ix<2;++ix)  normalize(_h[ix]);
57    }
58
59    /// @}
60
61
62    /// @name Histograms
63    /// @{
64    Histo1DPtr _h[2];
65    /// @}
66
67
68  };
69
70
71  RIVET_DECLARE_PLUGIN(CLEOC_2008_I784516);
72
73}