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BESIII_2022_I2088218

Mass distributions in the decay $D^+_s\to K^+\pi^+\pi^-\pi^0$
Experiment: BESIII (BEPC)
Inspire ID: 2088218
Status: VALIDATED NOHEPDATA
Authors:
  • Peter Richardson
References: Beams: * *
Beam energies: ANY
    No run details listed

Measurement of the mass distributions in the decay $D^+_s\to K^+\pi^+\pi^-\pi^0$ by BES. The data were read from the plots in the paper and therefore for some points the error bars are the size of the point. It is also not clear that any resolution effects have been unfolded.

Source code: BESIII_2022_I2088218.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  Ds -> K+pi+pi-pi0
10  class BESIII_2022_I2088218 : public Analysis {
11  public:
12
13    /// Constructor
14    RIVET_DEFAULT_ANALYSIS_CTOR(BESIII_2022_I2088218);
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::abspid==431);
24      declare(ufs, "UFS");
25      DecayedParticles DS(ufs);
26      DS.addStable(PID::PI0);
27      DS.addStable(PID::K0S);
28      declare(DS,"DS");
29      // histos
30      for(unsigned int ix=0;ix<10;++ix)
31	book(_h[ix],1,1,1+ix);
32    }
33
34    /// Perform the per-event analysis
35    void analyze(const Event& event) {
36      static const map<PdgId,unsigned int> & mode   = { { 211,1}, {-211,1}, { 321,1}, {111,1}};
37      static const map<PdgId,unsigned int> & modeCC = { { 211,1}, {-211,1}, {-321,1}, {111,1}};
38      DecayedParticles DS = apply<DecayedParticles>(event, "DS");
39      // loop over particles
40      for(unsigned int ix=0;ix<DS.decaying().size();++ix) {
41	int sign = 1;
42	if (DS.decaying()[ix].pid()>0 && DS.modeMatches(ix,4,mode)) {
43	  sign=1;
44	}
45	else if  (DS.decaying()[ix].pid()<0 && DS.modeMatches(ix,4,modeCC)) {
46	  sign=-1;
47	}
48	else
49	  continue;
50	const Particle & pip = DS.decayProducts()[ix].at( sign*211)[0];
51	const Particle & pim = DS.decayProducts()[ix].at(-sign*211)[0];
52	const Particle & Kp  = DS.decayProducts()[ix].at( sign*321)[0];
53	const Particle & pi0 = DS.decayProducts()[ix].at(      111)[0];
54	double mpipi = (pim.momentum()+pip.momentum()).mass();
55	if (mpipi>.46 && mpipi<.52) continue;
56	_h[0]->fill((Kp .momentum()+pim.momentum()).mass());
57	_h[1]->fill((Kp .momentum()+pi0.momentum()).mass());
58	_h[2]->fill(mpipi);
59	_h[3]->fill((pip.momentum()+pi0.momentum()).mass());
60	_h[4]->fill((pim.momentum()+pi0.momentum()).mass());
61	_h[5]->fill((Kp .momentum()+pim.momentum()+pi0.momentum()).mass());
62	_h[6]->fill((pip.momentum()+pim.momentum()+pi0.momentum()).mass());
63	_h[7]->fill((Kp .momentum()+pip.momentum()).mass());
64	_h[8]->fill((Kp .momentum()+pip.momentum()+pi0.momentum()).mass());
65	_h[9]->fill((Kp .momentum()+pip.momentum()+pim.momentum()).mass());
66      }
67    }
68
69
70    /// Normalise histograms etc., after the run
71    void finalize() {
72      for(unsigned int ix=0;ix<10;++ix)
73	normalize(_h[ix],1.,false);
74    }
75
76    /// @}
77
78
79    /// @name Histograms
80    /// @{
81    Histo1DPtr _h[10];
82    /// @}
83
84
85  };
86
87
88  RIVET_DECLARE_PLUGIN(BESIII_2022_I2088218);
89
90}