Rivet analyses

title: CUSB_1991_I325661

Inclusive $B^*$ cross-section above the $\Upsilon(4S)$

Experiment: CUSB (CESR)

Inspire ID: 325661

Status: VALIDATED

Authors: - Peter Richardson

References: - Phys.Rev.Lett. 67 (1991) 1692-1695

Beams: e- e+

Beam energies: (5.3, 5.3); (5.3, 5.3)GeV

Run details: - e+e- collisions

Measurement of the inclusive cross section for $B^*$ production at energies above the $\Upsilon(4S)$ mass.

Source code:CUSB_1991_I325661.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/UnstableParticles.hh"

namespace Rivet {

/// @brief e+e- > B* X class CUSB_1991_I325661 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(CUSB_1991_I325661);


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

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

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

  // Book histograms
  book(_c_Bstar, 1, 1, 1);
  for (const string& en : _c_Bstar.binning().edges<0>()) {
    const size_t idx = en.find("-");
    if (idx != string::npos) {
      const double emin = std::stod(en.substr(0, idx));
      const double emax = std::stod(en.substr(idx + 1, string::npos));
      if (inRange(sqrtS() / GeV, emin, emax)) {
        _sqs = en;
        break;
      }
    }
    else {
      const double eval = stod(en) * GeV;
      if (isCompatibleWithSqrtS(eval)) {
        _sqs = en;
        break;
      }
    }
  }
  raiseBeamErrorIf(_sqs.empty());
}


/// Perform the per-event analysis
void analyze(const Event& event) {
  const FinalState& ufs = apply<FinalState>(event, "UFS");
  unsigned int nBstar(0);
  // Get Bottom hadrons
  const Particles bhads = ufs.particles(Cuts::abspid == 513 or Cuts::abspid == 523);
  // find the Bstars
  for (const Particle& p : bhads) {
    if (p.abspid() == 513 || p.abspid() == 523) {
      if (!p.hasDescendantWith(Cuts::pid == p.pid())) ++nBstar;
    }
  }
  if (nBstar != 0) _c_Bstar->fill(_sqs, nBstar);
}


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

/// @}


/// @name Histograms
/// @{
BinnedHistoPtr<string> _c_Bstar;
string _sqs = "";
/// @}

};

RIVET_DECLARE_PLUGIN(CUSB_1991_I325661);

} ```