Rivet analyses reference

BESIII_2013_I1261765

$\psi(2S)\to \Lambda^0\bar\Sigma^\pm\pi^\mp$ + c.c.
Experiment: BESIII (BEPC)
Inspire ID: 1261765
Status: VALIDATED NOHEPDATA
Authors:

Peter Richardson

References:

Phys.Rev.D 88 (2013) 11, 112007

Beams: * *
Beam energies: ANY
Run details:

Any process producing psi(2S), originally e+e-

Measurements of mass distributions in the decays $\psi(2S)\to \Lambda^0\bar\Sigma^\pm\pi^\mp$ +c.c.. The data were read from the plots in the paper and may not be corrected for efficiency but the background given in the paper have been subtracted.

Source code: BESIII_2013_I1261765.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) -> Lambda Sigmabar+- pi-+
10  class BESIII_2013_I1261765 : public Analysis {
11  public:
12
13    /// Constructor
14    RIVET_DEFAULT_ANALYSIS_CTOR(BESIII_2013_I1261765);
15
16
17    /// @name Analysis methods
18    /// @{
19
20    /// Book histograms and initialise projections before the run
21    void init() {
22      UnstableParticles ufs = UnstableParticles(Cuts::pid==100443);
23      declare(ufs, "UFS");
24      DecayedParticles psi(ufs);
25      psi.addStable( PID::PI0);
26      psi.addStable( PID::K0S);
27      psi.addStable( PID::SIGMAPLUS);
28      psi.addStable( PID::SIGMAMINUS);
29      psi.addStable(-PID::SIGMAPLUS);
30      psi.addStable(-PID::SIGMAMINUS);
31      psi.addStable( PID::LAMBDA);
32      psi.addStable(-PID::LAMBDA);
33      declare(psi, "psi");
34      for(unsigned int ix=0;ix<3;++ix)
35	book(_h[ix],1,1,1+ix);
36    }
37
38
39    /// Perform the per-event analysis
40    void analyze(const Event& event) {
41      static const map<PdgId,unsigned int> & mode1   = { { 3122,1}, {-3222,1}, { 211,1} };
42      static const map<PdgId,unsigned int> & mode1CC = { {-3122,1}, { 3222,1}, {-211,1} };
43      static const map<PdgId,unsigned int> & mode2   = { { 3122,1}, {-3112,1}, {-211,1} };
44      static const map<PdgId,unsigned int> & mode2CC = { {-3122,1}, { 3112,1}, { 211,1} };
45      DecayedParticles psi = apply<DecayedParticles>(event, "psi");
46      for(unsigned int ix=0;ix<psi.decaying().size();++ix) {
47	int ipi=211, isigma=-3222,sign=1;
48	if(psi.modeMatches(ix,3,mode1)) {
49	  sign =  1;
50	}
51	else if(psi.modeMatches(ix,3,mode1CC)) {
52	  sign = -1;
53	}
54	else if(psi.modeMatches(ix,3,mode2)) {
55	  ipi=-211;
56	  isigma=-3112;
57	  sign =  1;
58	}
59	else if(psi.modeMatches(ix,3,mode2CC)) {
60	  ipi=-211;
61	  isigma=-3112;
62	  sign = -1;
63	} 
64	else
65	  continue;
66	const Particle & lam   = psi.decayProducts()[ix].at( sign*3122  )[0];
67	const Particle & pim   = psi.decayProducts()[ix].at( sign*ipi   )[0];
68	const Particle & sigma = psi.decayProducts()[ix].at( sign*isigma)[0];
69	_h[0]->fill((lam.momentum()+pim  .momentum()).mass());
70	_h[1]->fill((pim.momentum()+sigma.momentum()).mass());
71	_h[2]->fill((lam.momentum()+sigma.momentum()).mass());
72      }
73    }
74
75
76    /// Normalise histograms etc., after the run
77    void finalize() {
78      for(unsigned int ix=0;ix<3;++ix)
79	normalize(_h[ix],1.,false);
80    }
81
82    /// @}
83
84
85    /// @name Histograms
86    /// @{
87    Histo1DPtr _h[3];
88    /// @}
89
90
91  };
92
93
94  RIVET_DECLARE_PLUGIN(BESIII_2013_I1261765);
95
96}