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 -> D**  l nu
 10  class BELLE_2008_I768236 : public Analysis {
 11  public:
 12
 13    /// Constructor
 14    RIVET_DEFAULT_ANALYSIS_CTOR(BELLE_2008_I768236);
 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 || Cuts::abspid==521);
 24      declare(ufs, "UFS");
 25      DecayedParticles BB(ufs);
 26      BB.addStable(411); BB.addStable(-411);
 27      BB.addStable(421); BB.addStable(-421);
 28      BB.addStable(413); BB.addStable(-413);
 29      BB.addStable(423); BB.addStable(-423);
 30      BB.addStable(PID::PI0);
 31      declare(BB, "BB");
 32      // hists
 33      for (unsigned int ix=0; ix<4; ++ix) {
 34        book(_h_mass[ix], 1, 1, 1+ix);
 35        if (ix==3 || ix==1) continue;
 36        book(_h_hel [ix], 2, 1, 1+ix);
 37        book(_h_w   [ix], 3, 1, 1+ix);
 38      }
 39    }
 40
 41
 42    /// Perform the per-event analysis
 43    void analyze(const Event& event) {
 44      static const map<PdgId,unsigned int> mode1[4] = {{ {-411,1}, { 211,1}, {-11,1}, { 12,1}},
 45                                                       { { 411,1}, {-211,1}, { 11,1}, {-12,1}},
 46                                                       { {-411,1}, { 211,1}, {-13,1}, { 14,1}},
 47                                                       { { 411,1}, {-211,1}, { 13,1}, {-14,1}}};
 48      static const map<PdgId,unsigned int> mode2[4] = {{ {-413,1}, { 211,1}, {-11,1}, { 12,1}},
 49                                                       { { 413,1}, {-211,1}, { 11,1}, {-12,1}},
 50                                                       { {-413,1}, { 211,1}, {-13,1}, { 14,1}},
 51                                                       { { 413,1}, {-211,1}, { 13,1}, {-14,1}}};
 52      static const map<PdgId,unsigned int> mode3[4] = {{ {-421,1}, {-211,1}, {-11,1}, { 12,1}},
 53                                                       { { 421,1}, { 211,1}, { 11,1}, {-12,1}},
 54                                                       { {-421,1}, {-211,1}, {-13,1}, { 14,1}},
 55                                                       { { 421,1}, { 211,1}, { 13,1}, {-14,1}}};
 56      static const map<PdgId,unsigned int> mode4[4] = {{ {-423,1}, {-211,1}, {-11,1}, { 12,1}},
 57                                                       { { 423,1}, { 211,1}, { 11,1}, {-12,1}},
 58                                                       { {-423,1}, {-211,1}, {-13,1}, { 14,1}},
 59                                                       { { 423,1}, { 211,1}, { 13,1}, {-14,1}}};
 60      // loop over B mesons
 61      DecayedParticles BB = apply<DecayedParticles>(event, "BB");
 62      // loop over particles
 63      for (unsigned int ix=0; ix<BB.decaying().size(); ++ix) {
 64      	for (unsigned int il=0; il<4; ++il) {
 65          int iD,imode=0;
 66          if ( BB.modeMatches(ix,4,mode1[il]) ) {
 67            imode=0;
 68            iD=411;
 69          }
 70          else if ( BB.modeMatches(ix,4,mode2[il]) ) {
 71            imode=1;
 72            iD=413;
 73          }
 74          else if ( BB.modeMatches(ix,4,mode3[il]) ) {
 75            imode=2;
 76            iD=421;
 77          }
 78          else if ( BB.modeMatches(ix,4,mode4[il]) ) {
 79            imode=3;
 80            iD=423;
 81          }
 82          else continue;
 83          int sign = il%2==0 ? 1 : -1;
 84          int ipi = -sign*211;
 85          iD *= -sign;
 86          if(imode<2) ipi*=-1;
 87          const Particle & pi1= BB.decayProducts()[ix].at( ipi)[0];
 88          const Particle & DD = BB.decayProducts()[ix].at( iD )[0];
 89          FourMomentum pHad = pi1.mom()+DD.mom();
 90          double mass = pHad.mass();
 91          _h_mass[imode]->fill(mass);
 92          // just the D pi modes for helicty and w
 93          if (imode%2!=0) continue;
 94          // check ingtermediate
 95          int inter=-1;
 96          for (unsigned int iz=0;iz<BB.decaying()[ix].children().size();++iz) {
 97            if (BB.decaying()[ix].children()[iz].abspid()==10411 ||
 98                BB.decaying()[ix].children()[iz].abspid()==10421) {
 99              inter=0;
100              break;
101            }
102            else if (BB.decaying()[ix].children()[iz].abspid()==415 ||
103                     BB.decaying()[ix].children()[iz].abspid()==425) {
104              inter=2;
105              break;
106            }
107          }
108          if (inter<0) continue;
109          // First boost all relevant momenta into the B-rest frame
110          const LorentzTransform boost1 = LorentzTransform::mkFrameTransformFromBeta(BB.decaying()[ix].mom().betaVec());
111          // Momenta in B rest frame:
112          FourMomentum pDSS = boost1.transform(pHad);
113          FourMomentum pW   = boost1.transform(BB.decaying()[ix].mom() - pHad);
114          FourMomentum ppi  = boost1.transform(pi1);
115          const LorentzTransform boost2 = LorentzTransform::mkFrameTransformFromBeta(pDSS.betaVec());
116          double ctheta = pW.p3().unit().dot(boost2.transform(ppi).p3().unit());
117          _h_hel[inter]->fill(abs(ctheta));
118          double mB2 = BB.decaying()[ix].mom().mass2();
119          double mD2 = sqr(mass);
120          double w = (mB2 + mD2 - pW.mass2())/ (2. * sqrt(mB2) * sqrt(mD2) );
121          _h_w[inter]->fill(w);
122      	}
123      }
124    }
125
126
127    /// Normalise histograms etc., after the run
128    void finalize() {
129      normalize(_h_mass, 1.0, false);
130      normalize(_h_hel, 1.0, false);
131      normalize(_h_w, 1.0, false);
132    }
133
134    /// @}
135
136
137    /// @name Histograms
138    /// @{
139    Histo1DPtr _h_mass[4],_h_hel[3],_h_w[3];
140    /// @}
141
142
143  };
144
145
146  RIVET_DECLARE_PLUGIN(BELLE_2008_I768236);
147
148}