Rivet analyses referenceBABAR_2009_I785439Mass distributions in $B\to\eta K\gamma$ decaysExperiment: BABAR (PEP-II) Inspire ID: 785439 Status: VALIDATED NOHEPDATA Authors:
Beam energies: ANY Run details:
Mass distributions in $B\to\eta K\gamma$ decays Source code: BABAR_2009_I785439.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 B -> eta K gamma
10 class BABAR_2009_I785439 : public Analysis {
11 public:
12
13 /// Constructor
14 RIVET_DEFAULT_ANALYSIS_CTOR(BABAR_2009_I785439);
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==511||
24 Cuts::abspid==521);
25 declare(ufs, "UFS");
26 DecayedParticles BB(ufs);
27 BB.addStable(PID::ETA);
28 BB.addStable(PID::K0S);
29 declare(BB, "BB");
30 // histos
31 for(unsigned int ix=0;ix<2;++ix)
32 book(_h[ix],1,1,1+ix);
33 }
34
35
36 /// Perform the per-event analysis
37 void analyze(const Event& event) {
38 static const map<PdgId,unsigned int> & mode1 = { { 221,1},{ 310,1}, {22,1}};
39 static const map<PdgId,unsigned int> & mode2 = { { 221,1},{ 321,1}, {22,1}};
40 static const map<PdgId,unsigned int> & mode2CC = { { 221,1},{-321,1}, {22,1}};
41 DecayedParticles BB = apply<DecayedParticles>(event, "BB");
42 // loop over particles
43 for(unsigned int ix=0;ix<BB.decaying().size();++ix) {
44 int imode=0,sign = 1;
45 if(BB.decaying()[ix].abspid()==511) {
46 imode=1;
47 if (!BB.modeMatches(ix,3,mode1)) continue;
48 }
49 else {
50 imode=0;
51 if (BB.decaying()[ix].pid()>0 && BB.modeMatches(ix,3,mode2)) {
52 sign=1;
53 }
54 else if (BB.decaying()[ix].pid()<0 && BB.modeMatches(ix,3,mode2CC)) {
55 sign=-1;
56 }
57 else
58 continue;
59 }
60 const Particle & KK = BB.decayProducts()[ix].at(imode==0 ? sign*321 : 310)[0];
61 const Particle & eta = BB.decayProducts()[ix].at( 221)[0];
62 _h[imode]->fill((KK.momentum()+eta.momentum()).mass());
63 }
64 }
65
66
67 /// Normalise histograms etc., after the run
68 void finalize() {
69 for(unsigned int ix=0;ix<2;++ix)
70 normalize(_h[ix],1.,false);
71 }
72
73 /// @}
74
75
76 /// @name Histograms
77 /// @{
78 Histo1DPtr _h[2];
79 /// @}
80
81
82 };
83
84
85 RIVET_DECLARE_PLUGIN(BABAR_2009_I785439);
86
87}
|
