Rivet analyses

Hadronic mass distributions in B → D(*)π(π)ℓν decays

Experiment: BELLE (KEKB)

Inspire ID: 2512112

Status: VALIDATED NOHEPDATA

Authors: - Peter Richardson

References: - arXiv: 2211.09833

Beams: * *

Beam energies: ANY

Run details: - Any process produding b0 and B+, originally Upsilon(4S) decay

Measurement of the mass of the hadronic system in B → D(*)π(π)ℓν decays

Source code:BELLE_2022_I2512112.cc

// -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/DecayedParticles.hh"
#include "Rivet/Projections/UnstableParticles.hh"

namespace Rivet {


  /// @brief B -> D pi (pi) semileptonic
  class BELLE_2022_I2512112 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(BELLE_2022_I2512112);


    /// @name Analysis methods
    /// @{

    /// Book histograms and initialise projections before the run
    void init() {
      // Initialise and register projections
      UnstableParticles ufs = UnstableParticles(Cuts::abspid == 511 or Cuts::abspid == 521);
      declare(ufs, "UFS");
      DecayedParticles BB(ufs);
      BB.addStable(411);
      BB.addStable(-411);
      BB.addStable(421);
      BB.addStable(-421);
      BB.addStable(413);
      BB.addStable(-413);
      BB.addStable(423);
      BB.addStable(-423);
      BB.addStable(PID::PI0);
      declare(BB, "BB");
      // histograms
      for (unsigned int ix = 0; ix < 3; ++ix)
        for (unsigned int iy = 0; iy < 2; ++iy) book(_h[ix][iy], 1 + ix, 1, 1 + iy);
    }


    /// Perform the per-event analysis
    void analyze(const Event& event) {
      static const map<PdgId, unsigned int> mode1[4] = {{{-421, 1}, {-211, 1}, {-11, 1}, {12, 1}},
                                                        {{421, 1}, {211, 1}, {11, 1}, {-12, 1}},
                                                        {{-421, 1}, {-211, 1}, {-13, 1}, {14, 1}},
                                                        {{421, 1}, {211, 1}, {13, 1}, {-14, 1}}};
      static const map<PdgId, unsigned int> mode2[4] = {{{-411, 1}, {211, 1}, {-11, 1}, {12, 1}},
                                                        {{411, 1}, {-211, 1}, {11, 1}, {-12, 1}},
                                                        {{-411, 1}, {211, 1}, {-13, 1}, {14, 1}},
                                                        {{411, 1}, {-211, 1}, {13, 1}, {-14, 1}}};
      static const map<PdgId, unsigned int> mode3[4] = {{{-423, 1}, {-211, 1}, {-11, 1}, {12, 1}},
                                                        {{423, 1}, {211, 1}, {11, 1}, {-12, 1}},
                                                        {{-423, 1}, {-211, 1}, {-13, 1}, {14, 1}},
                                                        {{423, 1}, {211, 1}, {13, 1}, {-14, 1}}};
      static const map<PdgId, unsigned int> mode4[4] = {{{-413, 1}, {211, 1}, {-11, 1}, {12, 1}},
                                                        {{413, 1}, {-211, 1}, {11, 1}, {-12, 1}},
                                                        {{-413, 1}, {211, 1}, {-13, 1}, {14, 1}},
                                                        {{413, 1}, {-211, 1}, {13, 1}, {-14, 1}}};
      static const map<PdgId, unsigned int> mode5[4] = {{{-411, 1}, {-211, 1}, {211, 1}, {-11, 1}, {12, 1}},
                                                        {{411, 1}, {-211, 1}, {211, 1}, {11, 1}, {-12, 1}},
                                                        {{-411, 1}, {-211, 1}, {211, 1}, {-13, 1}, {14, 1}},
                                                        {{411, 1}, {-211, 1}, {211, 1}, {13, 1}, {-14, 1}}};
      static const map<PdgId, unsigned int> mode6[4] = {{{-421, 1}, {-211, 1}, {211, 1}, {-11, 1}, {12, 1}},
                                                        {{421, 1}, {-211, 1}, {211, 1}, {11, 1}, {-12, 1}},
                                                        {{-421, 1}, {-211, 1}, {211, 1}, {-13, 1}, {14, 1}},
                                                        {{421, 1}, {-211, 1}, {211, 1}, {13, 1}, {-14, 1}}};
      // loop over B mesons
      DecayedParticles BB = apply<DecayedParticles>(event, "BB");
      // loop over particles
      for (unsigned int ix = 0; ix < BB.decaying().size(); ++ix) {
        for (unsigned int il = 0; il < 4; ++il) {
          int iD, iloc1, iloc2;
          if (BB.modeMatches(ix, 4, mode1[il])) {
            iloc1 = 0;
            iloc2 = 0;
            iD = -421;
          }
          else if (BB.modeMatches(ix, 4, mode2[il])) {
            iloc1 = 0;
            iloc2 = 1;
            iD = -411;
          }
          else if (BB.modeMatches(ix, 4, mode3[il])) {
            iloc1 = 1;
            iloc2 = 0;
            iD = -423;
          }
          else if (BB.modeMatches(ix, 4, mode4[il])) {
            iloc1 = 1;
            iloc2 = 1;
            iD = -413;
          }
          else if (BB.modeMatches(ix, 5, mode5[il])) {
            iloc1 = 2;
            iloc2 = 0;
            iD = -411;
          }
          else if (BB.modeMatches(ix, 5, mode6[il])) {
            iloc1 = 2;
            iloc2 = 1;
            iD = -421;
          }
          else
            continue;
          int sign = il % 2 == 0 ? 1 : -1;
          int ipi = -sign * 211;
          if (iloc2 == 1) ipi *= -1;
          const Particle& pi1 = BB.decayProducts()[ix].at(ipi)[0];
          const Particle& DD = BB.decayProducts()[ix].at(iD * sign)[0];
          FourMomentum pHad = pi1.momentum() + DD.momentum();
          if (iloc1 == 2) {
            const Particle& pi2 = BB.decayProducts()[ix].at(-ipi)[0];
            pHad += pi2.momentum();
          }
          double mass = pHad.mass();
          if (iloc1 == 1) mass -= DD.mass();
          _h[iloc1][iloc2]->fill(mass);
        }
      }
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      for (unsigned int ix = 0; ix < 3; ++ix)
        for (unsigned int iy = 0; iy < 2; ++iy) normalize(_h[ix][iy], 1., false);
    }

    /// @}


    /// @name Histograms
    /// @{
    Histo1DPtr _h[3][2];
    /// @}
  };


  RIVET_DECLARE_PLUGIN(BELLE_2022_I2512112);

}