Rivet analyses

title: BABAR_2005_I686573

Mass distributions in $B^+\to p\bar{p}K^+$

Experiment: BABAR (PEP-II)

Inspire ID: 686573

Status: VALIDATED NOHEPDATA

Authors: - Peter Richardson

References: - Phys.Rev.D 72 (2005) 051101

Beams: * *

Beam energies: ANY

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

Measurement of mass distributions in $B^+\to p\bar{p}K^+$. The data were read from the plots in the paper and the backgrounds given subtracted.

Source code:BABAR_2005_I686573.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/DecayedParticles.hh"

include "Rivet/Projections/UnstableParticles.hh"

namespace Rivet {

/// @brief B+ -> p pbar K+ class BABAR_2005_I686573 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(BABAR_2005_I686573);


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

/// Book histograms and initialise projections before the run
void init() {
  // projections
  UnstableParticles ufs = UnstableParticles(Cuts::abspid == 521);
  declare(ufs, "UFS");
  DecayedParticles BP(ufs);
  BP.addStable(10441);
  BP.addStable(10443);
  BP.addStable(20443);
  BP.addStable(100443);
  BP.addStable(441);
  BP.addStable(445);
  declare(BP, "BP");
  // histos
  book(_h_pp, 1, 1, 1);
  for (unsigned int ix = 0; ix < 2; ++ix) book(_h_pK[ix], 2, 1, 1 + ix);
  book(_c, "TMP/nB");
}


/// Perform the per-event analysis
void analyze(const Event& event) {
  static const map<PdgId, unsigned int>& mode1 = {{2212, 1}, {-2212, 1}, {321, 1}};
  static const map<PdgId, unsigned int>& mode1CC = {{2212, 1}, {-2212, 1}, {-321, 1}};
  DecayedParticles BP = apply<DecayedParticles>(event, "BP");
  // loop over particles
  for (unsigned int ix = 0; ix < BP.decaying().size(); ++ix) {
    int sign = 1;
    if (BP.modeMatches(ix, 3, mode1))
      sign = 1;
    else if (BP.modeMatches(ix, 3, mode1CC))
      sign = -1;
    else
      continue;
    _c->fill();
    const Particle& pp = BP.decayProducts()[ix].at(sign * 2212)[0];
    const Particle& pbar = BP.decayProducts()[ix].at(-sign * 2212)[0];
    const Particle& Kp = BP.decayProducts()[ix].at(sign * 321)[0];
    _h_pp->fill((pp.momentum() + pbar.momentum()).mass());
    double mpK = (Kp.momentum() + pp.momentum()).mass();
    double mpbarK = (Kp.momentum() + pbar.momentum()).mass();
    if (mpK > mpbarK)
      _h_pK[0]->fill(mpK);
    else
      _h_pK[1]->fill(mpbarK);
  }
}


/// Normalise histograms etc., after the run
void finalize() {
  scale(_h_pp, 1. / *_c);
  for (unsigned int ix = 0; ix < 2; ++ix) scale(_h_pK[ix], 1. / *_c);
  Histo1DPtr tmp;
  book(tmp, 2, 1, 3);
  *tmp = *_h_pK[0] - *_h_pK[1];
  tmp->setPath("/" + name() + "/" + mkAxisCode(2, 1, 3));
}

/// @}


/// @name Histograms
/// @{
Histo1DPtr _h_pp, _h_pK[2];
CounterPtr _c;
/// @}

};

RIVET_DECLARE_PLUGIN(BABAR_2005_I686573);

} ```