Rivet analyses

Mass distribution in B− → Λc+Λ̄c−K−

Experiment: BABAR (PEP-II)

Inspire ID: 766290

Status: VALIDATED NOHEPDATA

Authors: - Peter Richardson

References: - Phys.Rev.D 77 (2008) 031101

Beams: * *

Beam energies: ANY

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

Measurement of mass distributions in B− → Λc+Λ̄c−K− decays. The data was read from plots in the paper, the data is not corrected for efficiency/acceptance although the sideband backgrounds given in the paper have been subtracted.

Source code:BABAR_2008_I766290.cc

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

namespace Rivet {


  /// @brief B- -> Lambda_c+ Lambdabar_c- K-
  class BABAR_2008_I766290 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(BABAR_2008_I766290);


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

    /// Book histograms and initialise projections before the run
    void init() {
      // Initialise and register projections
      UnstableParticles ufs = UnstableParticles(Cuts::abspid == PID::BPLUS);
      declare(ufs, "UFS");
      DecayedParticles BP(ufs);
      BP.addStable(4122);
      BP.addStable(-4122);
      declare(BP, "BP");
      // 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>& mode = {{4122, 1}, {-4122, 1}, {321, 1}};
      static const map<PdgId, unsigned int>& modeCC = {{4122, 1}, {-4122, 1}, {-321, 1}};
      DecayedParticles BP = apply<DecayedParticles>(event, "BP");
      for (unsigned int ix = 0; ix < BP.decaying().size(); ++ix) {
        // select right decay mode
        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& lam = BP.decayProducts()[ix].at(4122 * sign)[0];
        const Particle& lbar = BP.decayProducts()[ix].at(-4122 * sign)[0];
        const Particle& Kp = BP.decayProducts()[ix].at(321 * sign)[0];
        _h[0]->fill((lbar.momentum() + Kp.momentum()).mass());
        _h[1]->fill((lam.momentum() + lbar.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_I766290);

}