Rivet analyses referenceBABAR_2012_I1185407Mass distributions in $\tau^-\to2\pi^-\pi^+3\pi^0\nu_\tau$, $3\pi^-2\pi^+\nu_\tau$ and $3\pi^-2\pi^+\pi^0\nu_\tau$Experiment: BABAR (PEP-II) Inspire ID: 1185407 Status: VALIDATED NOHEPDATA Authors:
Beam energies: ANY Run details:
Measurement of mass distributions in $\tau^-\to2\pi^-\pi^+3\pi^0\nu_\tau$, $3\pi^-2\pi^+\nu_\tau$ and $3\pi^-2\pi^+\pi^0\nu_\tau$. The data were read from the plots in the paper and are not corrected, although the backgrounds given in the paper have been subtracted. The plots should therefore only be used for qualitative comparisons however the data is useful as there are not corrected distributions for this decay mode. Source code: BABAR_2012_I1185407.cc 1// -*- C++ -*-
2#include "Rivet/Analysis.hh"
3#include "Rivet/Projections/FinalState.hh"
4#include "Rivet/Projections/UnstableParticles.hh"
5#include "Rivet/Projections/DecayedParticles.hh"
6
7namespace Rivet {
8
9
10 /// @brief tau -> 5 and 5 pion final states
11 class BABAR_2012_I1185407 : public Analysis {
12 public:
13
14 /// Constructor
15 RIVET_DEFAULT_ANALYSIS_CTOR(BABAR_2012_I1185407);
16
17
18 /// @name Analysis methods
19 /// @{
20
21 /// Book histograms and initialise projections before the run
22 void init() {
23 // Initialise and register projections
24 UnstableParticles ufs = UnstableParticles(Cuts::abspid==15);
25 declare(ufs, "UFS");
26 DecayedParticles TAU(ufs);
27 TAU.addStable(310);
28 TAU.addStable(111);
29 declare(TAU, "TAU");
30 // histogram
31 for(unsigned int ix=0;ix<4;++ix) {
32 book(_h_6pi[ix],3,1,1+ix);
33 if(ix>2) continue;
34 book(_h_3pi[ix],1,1,1+ix);
35 book(_h_5pi[ix],2,1,1+ix);
36 }
37 }
38
39
40 /// Perform the per-event analysis
41 void analyze(const Event& event) {
42 static const map<PdgId,unsigned int> & mode1 = { {-211,2}, { 211,1},{111,3},{ 16,1}};
43 static const map<PdgId,unsigned int> & mode1CC = { { 211,2}, {-211,1},{111,3},{-16,1}};
44 static const map<PdgId,unsigned int> & mode2 = { {-211,3}, { 211,2},{ 16,1}};
45 static const map<PdgId,unsigned int> & mode2CC = { { 211,3}, {-211,2},{-16,1}};
46 static const map<PdgId,unsigned int> & mode3 = { {-211,3}, { 211,2},{111,1},{ 16,1}};
47 static const map<PdgId,unsigned int> & mode3CC = { { 211,3}, {-211,2},{111,1},{-16,1}};
48 DecayedParticles TAU = apply<DecayedParticles>(event, "TAU");
49 // loop over particles
50 for(unsigned int ix=0;ix<TAU.decaying().size();++ix) {
51 int sign = TAU.decaying()[ix].pid()>0 ? 1 : -1;
52 int imode=-1;
53 if(TAU.modeMatches(ix,7,mode1 ) ||
54 TAU.modeMatches(ix,7,mode1CC)) imode = 0;
55 else if(TAU.modeMatches(ix,6,mode2 ) ||
56 TAU.modeMatches(ix,6,mode2CC)) imode = 1;
57 else if(TAU.modeMatches(ix,7,mode3 ) ||
58 TAU.modeMatches(ix,7,mode3CC)) imode = 2;
59 else continue;
60 const Particles & pip = TAU.decayProducts()[ix].at( 211*sign);
61 const Particles & pim = TAU.decayProducts()[ix].at(-211*sign);
62 FourMomentum ptotal;
63 for(unsigned int ix=0;ix<pim.size();++ix) ptotal +=pim[ix].momentum();
64 for(unsigned int ix=0;ix<pip.size();++ix) ptotal +=pip[ix].momentum();
65 if(imode==1) {
66 _h_5pi[2]->fill(ptotal.mass());
67 for(unsigned int ix=0;ix<pim.size();++ix) {
68 _h_5pi[1]->fill((ptotal-pim[ix].momentum()).mass());
69 for(unsigned int iy=0;iy<pip.size();++iy) {
70 _h_5pi[0]->fill((pim[ix].momentum()+pip[iy].momentum()).mass());
71 }
72 }
73 }
74 else {
75 const Particles & pi0 = TAU.decayProducts()[ix].at(111);
76 FourMomentum ppi0;
77 for(unsigned int ix=0;ix<pi0.size();++ix) ppi0 +=pi0[ix].momentum();
78 ptotal+=ppi0;
79 if(imode==0 ) {
80 _h_3pi[0]->fill(ppi0.mass());
81 _h_3pi[2]->fill(ptotal.mass());
82 for(unsigned int ix=0;ix<pim.size();++ix) {
83 for(unsigned int iy=0;iy<pi0.size();++iy) {
84 _h_3pi[1]->fill((pip[0].momentum()+pim[ix].momentum()+pi0[iy].momentum()).mass());
85 }
86 }
87 }
88 else {
89 _h_6pi[3]->fill(ptotal.mass());
90 for(unsigned int ix=0;ix<pim.size();++ix) {
91 _h_6pi[2]->fill((ptotal-pim[ix].momentum()).mass());
92 for(unsigned int iy=0;iy<pip.size();++iy) {
93 _h_6pi[0]->fill((pim[ix].momentum()+pip[iy].momentum()).mass());
94 _h_6pi[1]->fill((pim[ix].momentum()+pip[iy].momentum()+pi0[0].momentum()).mass());
95 }
96 }
97 }
98 }
99 }
100 }
101
102 /// Normalise histograms etc., after the run
103 void finalize() {
104 for(unsigned int ix=0;ix<4;++ix) {
105 normalize(_h_6pi[ix]);
106 if(ix>2) continue;
107 normalize(_h_3pi[ix]);
108 normalize(_h_5pi[ix]);
109 }
110 }
111
112 /// @}
113
114
115 /// @name Histograms
116 /// @{
117 Histo1DPtr _h_3pi[3],_h_5pi[3],_h_6pi[4];
118 /// @}
119
120
121 };
122
123
124 RIVET_DECLARE_PLUGIN(BABAR_2012_I1185407);
125
126}
|