Rivet analyses

title: BELLE_2017_I1598461

Mass distributions in $B^+\to K^+K^-\pi^+$

Experiment: BELLE (KEKB)

Inspire ID: 1598461

Status: VALIDATED NOHEPDATA

Authors: - Peter Richardson

References: - Phys.Rev.D 96 (2017) 3, 031101

Beams: * *

Beam energies: ANY

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

Differential branching ratio and CP-asymmetry in the mass of the kaon pair for the decay $B^+\to K^+K^-\pi^+$.

Source code:BELLE_2017_I1598461.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/DecayedParticles.hh"

include "Rivet/Projections/UnstableParticles.hh"

namespace Rivet {

/// @brief B+ -> K+ K- pi+ class BELLE_2017_I1598461 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(BELLE_2017_I1598461);


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

/// Book histograms and initialise projections before the run
void init() {
  // Initialise and register projections
  UnstableParticles ufs = UnstableParticles(Cuts::abspid == 521);
  declare(ufs, "UFS");
  DecayedParticles BP(ufs);
  declare(BP, "BP");
  // book histograms
  for (unsigned int ix = 0; ix < 3; ++ix) {
    if (ix == 0)
      book(_h[ix], 1, 1, 1);
    else
      book(_h[ix], "TMP/h_" + toString(ix + 1), refData(1, 1, 1));
    book(_c[ix], "TMP/c_" + toString(ix + 1));
  }
}


/// Perform the per-event analysis
void analyze(const Event& event) {
  static const map<PdgId, unsigned int>& mode = {{321, 1}, {-321, 1}, {211, 1}};
  static const map<PdgId, unsigned int>& modeCC = {{321, 1}, {321, 1}, {-211, 1}};
  DecayedParticles BP = apply<DecayedParticles>(event, "BP");
  // loop over particles
  for (unsigned int ix = 0; ix < BP.decaying().size(); ++ix) {
    _c[0]->fill();
    if (BP.decaying()[ix].pid() > 0)
      _c[1]->fill();
    else
      _c[2]->fill();
    int sign = 1;
    if (BP.decaying()[ix].pid() > 0 && BP.modeMatches(ix, 3, mode)) {
      sign = 1;
    }
    else if (BP.decaying()[ix].pid() < 0 && BP.modeMatches(ix, 3, modeCC)) {
      sign = -1;
    }
    else
      continue;
    const Particle& Kp = BP.decayProducts()[ix].at(321)[0];
    const Particle& Km = BP.decayProducts()[ix].at(-321)[0];
    double mKK = (Kp.momentum() + Km.momentum()).mass();
    _h[0]->fill(mKK);
    if (sign == 1)
      _h[1]->fill(mKK);
    else
      _h[2]->fill(mKK);
  }
}


/// Normalise histograms etc., after the run
void finalize() {
  for (unsigned int ix = 0; ix < 3; ++ix) scale(_h[ix], 1e7 / *_c[ix]);
  Estimate1DPtr as;
  book(as, 1, 1, 2);
  asymm(_h[2], _h[1], as);
}

/// @}


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

};

RIVET_DECLARE_PLUGIN(BELLE_2017_I1598461);

} ```