Rivet analyses

Mass distributions in B± → KS0π±π0

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± → KS0π±π0. 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++ -*-
#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);

}