Rivet analyses

Ds(*)+K− mass distribution in B− → Ds(*)+K−π−

Experiment: BABAR (PEP-II)

Inspire ID: 755245

Status: VALIDATED NOHEPDATA

Authors: - Peter Richardson

References: - Phys.Rev.Lett. 100 (2008) 171803

Beams: * *

Beam energies: ANY

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

Measurement of the Ds(*)+K− mass distribution in B− → Ds(*)+K−π− by BaBar. The background subtracted data was read from Figure 3 in the paper.

Source code:BABAR_2008_I755245.cc

// -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/DecayedParticles.hh"
#include "Rivet/Projections/UnstableParticles.hh"

namespace Rivet {


  /// @brief B- -> D_s(*) K- pi-
  class BABAR_2008_I755245 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(BABAR_2008_I755245);


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

    /// Book histograms and initialise projections before the run
    void init() {
      // projections
      UnstableParticles ufs = UnstableParticles(Cuts::abspid == 521);
      declare(ufs, "UFS");
      DecayedParticles BB(ufs);
      BB.addStable(431);
      BB.addStable(-431);
      BB.addStable(433);
      BB.addStable(-433);
      BB.addStable(310);
      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) {
      static const map<PdgId, unsigned int>& mode1 = {{-431, 1}, {321, 1}, {211, 1}};
      static const map<PdgId, unsigned int>& mode1CC = {{431, 1}, {-321, 1}, {-211, 1}};
      static const map<PdgId, unsigned int>& mode2 = {{-433, 1}, {321, 1}, {211, 1}};
      static const map<PdgId, unsigned int>& mode2CC = {{433, 1}, {-321, 1}, {-211, 1}};
      DecayedParticles BB = apply<DecayedParticles>(event, "BB");
      for (unsigned int ix = 0; ix < BB.decaying().size(); ++ix) {
        int sign = 1, imode = 0;
        if (BB.decaying()[ix].pid() > 0 && BB.modeMatches(ix, 3, mode1)) {
          imode = 0;
          sign = 1;
        }
        else if (BB.decaying()[ix].pid() < 0 && BB.modeMatches(ix, 3, mode1CC)) {
          imode = 0;
          sign = -1;
        }
        else if (BB.decaying()[ix].pid() > 0 && BB.modeMatches(ix, 3, mode2)) {
          imode = 1;
          sign = 1;
        }
        else if (BB.decaying()[ix].pid() < 0 && BB.modeMatches(ix, 3, mode2CC)) {
          imode = 1;
          sign = -1;
        }
        else
          continue;
        const Particle& Kp = BB.decayProducts()[ix].at(sign * 321)[0];
        const Particle& Ds = BB.decayProducts()[ix].at(-sign * (431 + 2 * imode))[0];
        _h[imode]->fill((Kp.momentum() + Ds.momentum()).mass());
      }
    }


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

    /// @}


    /// @name Histograms
    /// @{
    Histo1DPtr _h[2];
    /// @}
  };


  RIVET_DECLARE_PLUGIN(BABAR_2008_I755245);

}