Rivet analyses

title: BABAR_2017_I1336340

Mass distributions in $B^\pm\to K^0_S \pi^\pm\pi^0$

Experiment: BABAR (PEP-II)

Inspire ID: 1336340

Status: VALIDATED NOHEPDATA

Authors: - Peter Richardson

References: - Phys.Rev.D 96 (2017) 7, 072001

Beams: * *

Beam energies: ANY

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

Mass distributions in $B^\pm\to K^0_S \pi^\pm\pi^0$. The data were read from the plot in the paper and the backgrounds given subtracted, however the backgrounds are large.

Source code:BABAR_2017_I1336340.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/DecayedParticles.hh"

include "Rivet/Projections/UnstableParticles.hh"

namespace Rivet {

/// @brief B+ -> KS0 pi+ pi0 class BABAR_2017_I1336340 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(BABAR_2017_I1336340);


/// @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(310);
  BP.addStable(111);
  declare(BP, "BP");
  // histograms
  for (unsigned int ix = 0; ix < 3; ++ix) {
    book(_h_sum[ix], 1, 1, 1 + ix);
    for (unsigned int iy = 0; iy < 2; ++iy) book(_h_charge[iy][ix], 2, 1 + iy, 1 + ix);
  }
}


/// Perform the per-event analysis
void analyze(const Event& event) {
  static const map<PdgId, unsigned int>& mode = {{211, 1}, {111, 1}, {310, 1}};
  static const map<PdgId, unsigned int>& modeCC = {{-211, 1}, {111, 1}, {310, 1}};
  DecayedParticles BP = apply<DecayedParticles>(event, "BP");
  for (unsigned int ix = 0; ix < BP.decaying().size(); ++ix) {
    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& pip = BP.decayProducts()[ix].at(sign * 211)[0];
    const Particle& pi0 = BP.decayProducts()[ix].at(111)[0];
    const Particle& K0 = BP.decayProducts()[ix].at(310)[0];
    double mKpip = (K0.momentum() + pip.momentum()).mass();
    double mKpi0 = (K0.momentum() + pi0.momentum()).mass();
    // veto D decaysa
    if (mKpi0 > 1.804 && mKpi0 < 1.924) continue;
    double mpipi = (pi0.momentum() + pip.momentum()).mass();
    _h_sum[0]->fill(mKpip);
    _h_sum[1]->fill(mKpi0);
    _h_sum[2]->fill(mpipi);
    _h_charge[(1 - sign) / 2][0]->fill(mKpip);
    _h_charge[(1 - sign) / 2][1]->fill(mKpi0);
    _h_charge[(1 - sign) / 2][2]->fill(mpipi);
  }
}


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

/// @}


/// @name Histograms
/// @{
Histo1DPtr _h_sum[3], _h_charge[2][3];
/// @}

};

RIVET_DECLARE_PLUGIN(BABAR_2017_I1336340);

} ```