Rivet analyses

title: BELLE_2015_I1411223

Cross section for $(BB^)^\pm\pi^\mp$ and $(B^B^*)^\pm\pi^\mp$ for $\sqrt{s}=10.866$ GeV

Experiment: BELLE (KEKB)

Inspire ID: 1411223

Status: VALIDATED NOHEPDATA

Authors: - Peter Richardson

References: - Phys.Rev.Lett. 116 (2016) 21, 212001

Beams: e+ e-

Beam energies: (5.4, 5.4)GeV

Run details: - e+ e- to hadrons, pi0 set stable

Measurement of the cross section for $(BB^)^\pm\pi^\mp$ and $(B^B^*)^\pm\pi^\mp$ at $\sqrt{s}=10.866$ GeV.

Source code:BELLE_2015_I1411223.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/FinalState.hh"

include "Rivet/Projections/UnstableParticles.hh"

namespace Rivet {

/// @brief e+e- > B() B pi class BELLE_2015_I1411223 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(BELLE_2015_I1411223);


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

/// Book histograms and initialise projections before the run
void init() {
  // projections
  declare(FinalState(), "FS");
  // histograms
  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) {
  Particles fs = apply<FinalState>(event, "FS").particles();
  Particles BB, other;
  for (const Particle& p : fs) {
    Particle parent = p;
    while (!parent.parents().empty()) {
      parent = parent.parents()[0];
      if (parent.abspid() == 511 || parent.abspid() == 521 || parent.abspid() == 513
          || parent.abspid() == 523)
        break;
    }
    if ((parent.abspid() == 511 || parent.abspid() == 521) && !parent.parents().empty()) {
      Particle Bstar = parent.parents()[0];
      if (Bstar.abspid() == 513 || Bstar.abspid() == 523) {
        parent = Bstar;
      }
    }
    if (parent.abspid() == 511 || parent.abspid() == 521 || parent.abspid() == 513
        || parent.abspid() == 523) {
      bool found = false;
      for (const auto& B : BB) {
        // B already in list
        if (fuzzyEquals(B.mom(), parent.mom())) {
          found = true;
          break;
        }
      }
      if (!found) BB += parent;
    }
    else {
      other += p;
    }
  }
  // B Bbar + charged pion
  if (BB.size() != 2 || other.size() != 1) vetoEvent;
  if (BB[0].pid() * BB[1].pid() > 0) vetoEvent;
  if (other[0].abspid() != 211) vetoEvent;
  if (BB[0].abspid() % 10 != 3) swap(BB[0], BB[1]);
  // B0 B*- pi+ +cc
  if ((BB[0].pid() == -513 && BB[1].pid() == 521 && other[0].pid() == -211)
      || (BB[0].pid() == 513 && BB[1].pid() == -521 && other[0].pid() == 211)
      || (BB[0].pid() == 523 && BB[1].pid() == -511 && other[0].pid() == -211)
      || (BB[0].pid() == -523 && BB[1].pid() == 511 && other[0].pid() == 211)) {
    _h[0]->fill("10.866"s);
  }
  else if ((BB[0].pid() == -513 && BB[1].pid() == 523 && other[0].pid() == -211)
           || (BB[0].pid() == 513 && BB[1].pid() == -523 && other[0].pid() == 211)
           || (BB[0].pid() == 523 && BB[1].pid() == -513 && other[0].pid() == -211)
           || (BB[0].pid() == -523 && BB[1].pid() == 513 && other[0].pid() == 211)) {
    _h[1]->fill("10.866"s);
  }
}


/// Normalise histograms etc., after the run
void finalize() {
  scale(_h, crossSection() / sumOfWeights() / picobarn);
}

/// @}


/// @name Histograms
/// @{
BinnedHistoPtr<string> _h[2];
/// @}

};

RIVET_DECLARE_PLUGIN(BELLE_2015_I1411223);

} ```