Rivet analyses

title: ARGUS_1993_I357133

Electron spectra in $B$ decays

Experiment: ARGUS (DORIS)

Inspire ID: 357133

Status: VALIDATED NOHEPDATA

Authors: - Peter Richardson

References: - Phys.Lett.B 318 (1993) 397-404

Beams: * *

Beam energies: ANY

Run details: - Bottom mesons produced at the Upsilon(4S)

Measurement of the primary and secondary lepton spetrum in $B$ decays by ARGUS. The corrected spectra read from figures 4 and 5 in the paper.

Source code:ARGUS_1993_I357133.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/UnstableParticles.hh"

namespace Rivet {

/// @brief B -> e spectrum class ARGUS_1993_I357133 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(ARGUS_1993_I357133);


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

/// Book histograms and initialise projections before the run
void init() {
  // projections
  declare(UnstableParticles(), "UFS");
  // histograms
  for (unsigned int ix = 0; ix < 2; ++ix) {
    book(_h[ix], 1 + ix, 1, 1);
  }
  book(_c, "TMP/nb");
}

void findDecayProducts(const Particle& parent,
                       vector<Particles>& em,
                       vector<Particles>& ep,
                       vector<Particles>& nue,
                       vector<Particles>& nueBar,
                       bool& charm,
                       bool secondary) {
  for (const Particle& p : parent.children()) {
    if (PID::isCharmHadron(p.pid())) {
      charm = true;
      findDecayProducts(p, em, ep, nue, nueBar, charm, true);
    }
    else if (p.pid() == PID::EMINUS) {
      em[secondary].push_back(p);
    }
    else if (p.pid() == PID::EPLUS) {
      ep[secondary].push_back(p);
    }
    else if (p.pid() == PID::NU_E) {
      nue[secondary].push_back(p);
    }
    else if (p.pid() == PID::NU_EBAR) {
      nueBar[secondary].push_back(p);
    }
    else if (PID::isBottomHadron(p.pid())) {
      findDecayProducts(p, em, ep, nue, nueBar, charm, false);
    }
    else if (!PID::isHadron(p.pid())) {
      findDecayProducts(p, em, ep, nue, nueBar, charm, secondary);
    }
  }
}

/// Perform the per-event analysis
void analyze(const Event& event) {
  const UnstableParticles& ufs = apply<UnstableParticles>(event, "UFS");
  for (const Particle& p : ufs.particles(Cuts::pid == 300553)) {
    // boost to rest frame
    LorentzTransform cms_boost;
    if (p.p3().mod() > 1 * MeV) {
      cms_boost = LorentzTransform::mkFrameTransformFromBeta(p.mom().betaVec());
    }
    // loop over decay products
    for (const Particle& p2 : p.children()) {
      if (p2.abspid() == 511 || p2.abspid() == 521) {
        _c->fill();
        // find decay products
        bool charm = false;
        vector<Particles> em(2), ep(2), nue(2), nueBar(2);
        findDecayProducts(p2, em, ep, nue, nueBar, charm, false);
        for (unsigned int isec = 0; isec < 2; ++isec) {
          FourMomentum pl, pnu;
          if (em[isec].size() == 1 && nueBar[isec].size() == 1
              && em[isec][0].pid() + 1 == -nueBar[isec][0].pid()) {
            pl = cms_boost.transform(em[isec][0].mom());
            pnu = cms_boost.transform(nueBar[isec][0].mom());
          }
          else if (ep[isec].size() == 1 && nue[isec].size() == 1
                   && nue[isec][0].pid() == -ep[isec][0].pid() + 1) {
            pl = cms_boost.transform(ep[isec][0].mom());
            pnu = cms_boost.transform(nue[isec][0].mom());
          }
          else {
            continue;
          }
          _h[isec]->fill(pl.p3().mod());
        }
      }
    }
  }
}


/// Normalise histograms etc., after the run
void finalize() {
  scale(_h, 1.0 / *_c);
}

/// @}


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

};

RIVET_DECLARE_PLUGIN(ARGUS_1993_I357133);

} ```