Rivet analyses referenceBABAR_2006_I713862$\bar{B}^0\to D^{*+} \omega\pi^-$ decaysExperiment: BABAR (PEP-II) Inspire ID: 713862 Status: VALIDATED NOHEPDATA Authors:
Beam energies: ANY Run details:
Measurement of mass distributions and the $D^{*+}$ polarization in $\bar{B}^0\to D^{*+} \omega\pi^-$ decays. The background subtracted/corrected data for the mass distributions was read from the figures in the paper and the polarization from Table 1. Source code: BABAR_2006_I713862.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 Bbar0 -> D*+ omega pi-
10 class BABAR_2006_I713862 : public Analysis {
11 public:
12
13 /// Constructor
14 RIVET_DEFAULT_ANALYSIS_CTOR(BABAR_2006_I713862);
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::abspid==511);
23 declare(ufs, "UFS");
24 DecayedParticles BB(ufs);
25 BB.addStable(PID::PI0);
26 BB.addStable( 413);
27 BB.addStable(-413);
28 BB.addStable(223);
29 declare(BB, "BB");
30 // histos
31 for(unsigned int ix=0;ix<2;++ix)
32 book(_h[ix],1+ix,1,1);
33 book(_p,3,1,1);
34 book(_c,"TMP/nB");
35 }
36
37
38 /// Perform the per-event analysis
39 void analyze(const Event& event) {
40 static const map<PdgId,unsigned int> & mode1 = { { -413,1}, { 211,1}, { 223,1}};
41 static const map<PdgId,unsigned int> & mode1CC = { { 413,1}, {-211,1}, { 223,1}};
42 // loop over particles
43 DecayedParticles BB = apply<DecayedParticles>(event, "BB");
44 for(unsigned int ix=0;ix<BB.decaying().size();++ix) {
45 _c->fill();
46 int sign = BB.decaying()[ix].pid()/BB.decaying()[ix].abspid();
47 if ( (sign== 1 && BB.modeMatches(ix,3,mode1) ) ||
48 (sign==-1 && BB.modeMatches(ix,3,mode1CC) ) ) {
49 const Particle & omega = BB.decayProducts()[ix].at( 223)[0];
50 const Particle & pim = BB.decayProducts()[ix].at( sign*211)[0];
51 const Particle & Dstar = BB.decayProducts()[ix].at(-sign*413)[0];
52 double mX = (omega.momentum()+pim.momentum()).mass();
53 _h[0]->fill(sqr(mX));
54 if(Dstar.children().size()!=2) continue;
55 // boost to B rest frame
56 LorentzTransform boost1 =
57 LorentzTransform::mkFrameTransformFromBeta(BB.decaying()[ix].momentum().betaVec());
58 FourMomentum pDpi = boost1.transform(Dstar.momentum()+pim.momentum());
59 LorentzTransform boost2 =
60 LorentzTransform::mkFrameTransformFromBeta(pDpi.betaVec());
61 FourMomentum pDstar = boost2.transform(boost1.transform(Dstar.momentum()));
62 double c1 = pDstar.p3().unit().dot(pDpi.p3().unit());
63 if(c1<0.5) _h[1]->fill(pDpi.mass());
64 Particle D0;
65 if(Dstar.children()[0].pid() ==-sign*211 &&
66 Dstar.children()[1].abspid()==-sign*421)
67 D0 = Dstar.children()[1];
68 else if(Dstar.children()[1].pid() ==-sign*211 &&
69 Dstar.children()[0].abspid()==-sign*421)
70 D0 = Dstar.children()[0];
71 else
72 continue;
73 FourMomentum pD0 = boost2.transform(boost1.transform(D0 .momentum()));
74 LorentzTransform boost3 = LorentzTransform::mkFrameTransformFromBeta(pDstar.betaVec());
75 pD0 = boost3.transform(pD0);
76 double cTheta = pD0.p3().unit().dot(pDstar.p3().unit());
77 _p->fill(mX,.5*(5.*sqr(cTheta)-1.));
78 }
79 }
80 }
81
82
83 /// Normalise histograms etc., after the run
84 void finalize() {
85 // first hist is differential BR/ BR for leptons
86 double br = .1033;
87 scale(_h[0], 1./br/ *_c);
88 normalize(_h[1],1.,false);
89 }
90
91 /// @}
92
93
94 /// @name Histograms
95 /// @{
96 Histo1DPtr _h[2];
97 Profile1DPtr _p;
98 CounterPtr _c;
99 /// @}
100
101
102 };
103
104
105 RIVET_DECLARE_PLUGIN(BABAR_2006_I713862);
106
107}
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