Rivet analyses

title: BELLE_2011_I897683

$\phi K$ mass distribution in $B^{+,0}\to\phi K^{+,0}\gamma$ decays

Experiment: BELLE (KEKB)

Inspire ID: 897683

Status: VALIDATED NOHEPDATA

Authors: - Peter Richardson

References: - Phys.Rev.D 84 (2011) 071101

Beams: * *

Beam energies: ANY

Run details: - Any process producing B+ and B0 mesons

Measurement of the $\phi K$ mass distribution in $B^{+,0}\to\phi K^{+,0}\gamma$ decays. The data was read from the plots in the paper whcih are background subtracted and efficiency corrected.

Source code:BELLE_2011_I897683.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/DecayedParticles.hh"

include "Rivet/Projections/UnstableParticles.hh"

namespace Rivet {

/// @brief B -> phi K gamma class BELLE_2011_I897683 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(BELLE_2011_I897683);


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

/// Book histograms and initialise projections before the run
void init() {
  // Initialise and register projections
  UnstableParticles ufs = UnstableParticles(Cuts::abspid == 511 || Cuts::abspid == 521);
  declare(ufs, "UFS");
  DecayedParticles BB(ufs);
  BB.addStable(PID::PHI);
  BB.addStable(PID::K0S);
  declare(BB, "BB");
  // histos
  for (unsigned int ix = 0; ix < 2; ++ix) {
    book(_h[ix], 1, 1, 1 + ix);
  }
}


/// 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 = 1, imode = 0, iK = 321;
    if (BB.decaying()[ix].abspid() == 521) {
      if (BB.decaying()[ix].pid() > 0 && BB.modeMatches(ix, 3, mode1)) {
        sign = 1;
      }
      else if (BB.decaying()[ix].pid() < 0 && BB.modeMatches(ix, 3, mode1CC)) {
        sign = -1;
      }
      else {
        continue;
      }
    }
    else if (BB.modeMatches(ix, 3, mode2)) {
      imode = 1;
      iK = 310;
    }
    else {
      continue;
    }
    const Particle& K = BB.decayProducts()[ix].at(sign * iK)[0];
    const Particle& phi = BB.decayProducts()[ix].at(333)[0];
    _h[imode]->fill((K.mom() + phi.mom()).mass());
  }
}


/// Normalise histograms etc., after the run
void finalize() {
  normalize(_h, 1., false);
}

/// @}


/// @name Histograms
/// @{
Histo1DPtr _h[2];
const map<PdgId, unsigned int> mode1 = {{333, 1}, {321, 1}, {22, 1}};
const map<PdgId, unsigned int> mode1CC = {{333, 1}, {-321, 1}, {22, 1}};
const map<PdgId, unsigned int> mode2 = {{333, 1}, {310, 1}, {22, 1}};
/// @}

};

RIVET_DECLARE_PLUGIN(BELLE_2011_I897683);

} ```