Rivet analyses

title: L3_1995_I381046

Production of $B^*$ mesons at LEP1

Experiment: L3 (LEP)

Inspire ID: 381046

Status: VALIDATED

Authors: - Peter Richardson

References: - Phys.Lett. B345 (1995) 589-597, 1995

Beams: e- e+

Beam energies: (45.6, 45.6)GeV

Run details: - e+e- to hadrons

The ratio of vector to pseudoscalar for $B$ meson production at LEP1.

Source code:L3_1995_I381046.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/ChargedFinalState.hh"

include "Rivet/Projections/UnstableParticles.hh"

namespace Rivet {

/// @brief B* production class L3_1995_I381046 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(L3_1995_I381046);


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

/// Book histograms and initialise projections before the run
void init() {

  // // Initialise and register projections
  declare(ChargedFinalState(), "FS");
  declare(UnstableParticles(), "UFS");

  // Book histograms
  book(_c_bStar, "/TMP/cbStar", refData<YODA::BinnedEstimate<string>>(1, 1, 1));
  book(_c_B, "/TMP/cB", refData<YODA::BinnedEstimate<string>>(1, 1, 1));
}


/// Perform the per-event analysis
void analyze(const Event& event) {
  // First, veto on leptonic events by requiring at least 4 charged FS particles
  const FinalState& fs = apply<FinalState>(event, "FS");
  const size_t numParticles = fs.particles().size();

  // Even if we only generate hadronic events, we still need a cut on numCharged >= 2.
  if (numParticles < 2) {
    MSG_DEBUG("Failed leptonic event cut");
    vetoEvent;
  }
  MSG_DEBUG("Passed leptonic event cut");

  for (const Particle& p : apply<UnstableParticles>(event, "UFS")
                               .particles(Cuts::abspid == 513 or Cuts::abspid == 523
                                          or Cuts::abspid == 511 or Cuts::abspid == 521)) {
    // count number of Bs not from mixing or B*
    if (p.abspid() == 511 || p.abspid() == 521) {
      if (p.parents()[0].abspid() == p.abspid()) continue;
      if (p.parents()[0].abspid() == 513 || p.parents()[0].abspid() == 523) continue;
      _c_B->fill(Ecm);
    }
    else {
      _c_bStar->fill(Ecm); // B*
    }
  }
}


/// Normalise histograms etc., after the run
void finalize() {
  // no of B*/B+B*
  BinnedEstimatePtr<string> h1;
  book(h1, 1, 1, 1);
  divide(*_c_bStar, (*_c_bStar + *_c_B), h1);
}

/// @}


/// @name Histograms
/// @{
BinnedHistoPtr<string> _c_bStar, _c_B;
const string Ecm = "91.2";
/// @}

};

RIVET_DECLARE_PLUGIN(L3_1995_I381046);

} ```