Rivet analyses

title: BELLE_2005_I679165

Differential branching ratios in $B^+\to p\bar{p}K^+$, $B^0\to p\bar{p}K^0_S$ and $B^0\to p\bar{\Lambda}\pi^-$

Experiment: BELLE (KEKB)

Inspire ID: 679165

Status: VALIDATED NOHEPDATA

Authors: - Peter Richardson

References: - Phys.Lett.B 617 (2005) 141-149

Beams: * *

Beam energies: ANY

Run details: - Any process producing B+ mesons, originally Upsilon(4S) decays

Differential branching ratios in $B^+\to p\bar{p}K^+$, $B^0\to p\bar{p}K^0_S$ and $B^0\to p\bar{\Lambda}\pi^-$.The corrected data was read from the figures in the paper.

Source code:BELLE_2005_I679165.cc

```c++ // -- C++ --

include "Rivet/Analysis.hh"

include "Rivet/Projections/DecayedParticles.hh"

include "Rivet/Projections/UnstableParticles.hh"

namespace Rivet {

/// @brief B -> p pbar K or p Lambdabar pi class BELLE_2005_I679165 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(BELLE_2005_I679165);


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

/// Book histograms and initialise projections before the run
void init() {
  // projections
  UnstableParticles ufs = UnstableParticles(Cuts::abspid == 511 || Cuts::abspid == 521);
  declare(ufs, "UFS");
  DecayedParticles BB(ufs);
  BB.addStable(310);
  BB.addStable(3122);
  BB.addStable(-3122);
  declare(BB, "BB");
  // histograms
  for (unsigned int ix = 0; ix < 4; ++ix) {
    book(_h_angle[ix], 2, 1, 1 + ix);
    if (ix == 3) continue;
    book(_h_mass[ix], 1, 1, 1 + ix);
  }
  for (unsigned int ix = 0; ix < 2; ++ix) {
    book(_c[ix], "TMP/nB_" + toString(ix + 1));
  }
}


/// Perform the per-event analysis
void analyze(const Event& event) {
  DecayedParticles BB = apply<DecayedParticles>(event, "BB");
  // loop over particles
  for (unsigned int ix = 0; ix < BB.decaying().size(); ++ix) {
    int sign = BB.decaying()[ix].pid() / BB.decaying()[ix].abspid();
    int imode = -1;
    if (BB.decaying()[ix].abspid() == 511)
      _c[0]->fill();
    else
      _c[1]->fill();
    if ((sign > 0 && BB.modeMatches(ix, 3, mode1)) || (sign < 0 && BB.modeMatches(ix, 3, mode1CC)))
      imode = 0;
    else if ((sign > 0 && BB.modeMatches(ix, 3, mode2)) || (sign < 0 && BB.modeMatches(ix, 3, mode2CC)))
      imode = 1;
    else if ((sign > 0 && BB.modeMatches(ix, 3, mode3)) || (sign < 0 && BB.modeMatches(ix, 3, mode3CC)))
      imode = 2;
    else {
      continue;
    }
    // boost to B rest frame
    LorentzTransform boost = LorentzTransform::mkFrameTransformFromBeta(
        BB.decaying()[ix].mom().betaVec());
    if (imode < 2) {
      const Particle& pp = BB.decayProducts()[ix].at(sign * 2212)[0];
      const Particle& pbar = BB.decayProducts()[ix].at(-sign * 2212)[0];
      const Particle& meson = BB.decayProducts()[ix].at(imode == 0 ? sign * 321 : 310)[0];
      FourMomentum pbaryon = pp.mom() + pbar.mom();
      double mass = pbaryon.mass();
      if (2.850 < mass && mass < 3.12) continue;
      if (3.315 < mass && mass < 3.735) continue;
      _h_mass[imode]->fill(mass);
      if (mass > 2.85) continue;
      FourMomentum pp1 = boost.transform(pp.mom());
      pbaryon = boost.transform(pbaryon);
      Vector3 axis = boost.transform(meson.mom()).p3().unit();
      LorentzTransform boost1 = LorentzTransform::mkFrameTransformFromBeta(pbaryon.betaVec());
      double cosp = axis.dot(boost1.transform(pp1).p3().unit());
      _h_angle[imode]->fill(cosp);
    }
    else {
      const Particle& pp = BB.decayProducts()[ix].at(sign * 2212)[0];
      const Particle& lbar = BB.decayProducts()[ix].at(-sign * 3122)[0];
      const Particle& meson = BB.decayProducts()[ix].at(-sign * 211)[0];
      FourMomentum pbaryon = pp.mom() + lbar.mom();
      double mass = pbaryon.mass();
      _h_mass[imode]->fill(mass);
      FourMomentum pp1 = boost.transform(pp.mom());
      FourMomentum pppi = pp.mom() + meson.mom();
      LorentzTransform boost2 = LorentzTransform::mkFrameTransformFromBeta(pppi.betaVec());
      Vector3 axis = boost.transform(lbar.mom()).p3().unit();
      double cosp = axis.dot(boost2.transform(pp1).p3().unit());
      _h_angle[3]->fill(cosp);
      if (mass > 2.85) continue;
      pbaryon = boost.transform(pbaryon);
      axis = boost.transform(meson.mom()).p3().unit();
      LorentzTransform boost1 = LorentzTransform::mkFrameTransformFromBeta(pbaryon.betaVec());
      cosp = axis.dot(boost1.transform(pp1).p3().unit());
      _h_angle[imode]->fill(cosp);
    }
  }
}


/// Normalise histograms etc., after the run
void finalize() {
  scale(_h_mass[0], 1e6 / *_c[1]);
  scale(_h_mass[1], 1e6 / *_c[0]);
  scale(_h_mass[2], 1e6 / *_c[0]);
  scale(_h_angle[0], 1e6 / *_c[1]);
  for (unsigned int ix = 1; ix < 4; ++ix) {
    scale(_h_angle[ix], 1e6 / *_c[0]);
  }
}

/// @}


/// @name Histograms
/// @{
Histo1DPtr _h_mass[3], _h_angle[4];
CounterPtr _c[2];
const map<PdgId, unsigned int> mode1 = {{2212, 1}, {-2212, 1}, {321, 1}};
const map<PdgId, unsigned int> mode1CC = {{2212, 1}, {-2212, 1}, {-321, 1}};
const map<PdgId, unsigned int> mode2 = {{2212, 1}, {-2212, 1}, {310, 1}};
const map<PdgId, unsigned int> mode2CC = {{2212, 1}, {-2212, 1}, {310, 1}};
const map<PdgId, unsigned int> mode3 = {{2212, 1}, {-3122, 1}, {-211, 1}};
const map<PdgId, unsigned int> mode3CC = {{-2212, 1}, {3122, 1}, {211, 1}};
/// @}

};

RIVET_DECLARE_PLUGIN(BELLE_2005_I679165);

} ```