Rivet analyses

title: LHCB_2019_I1760257

Ratio of strange to non-strange B meson production at 7,8 and 13 TeV

Experiment: LHCB (LHC)

Inspire ID: 1760257

Status: VALIDATED NOHEPDATA

Authors: - Peter Richardson

References: - Phys.Rev.Lett. 124 (2020) 12, 122002

Beams: p+ p+

Beam energies: (3500.0, 3500.0); (4000.0, 4000.0); (6500.0, 6500.0)GeV

Run details: - b hadron production

Ratio of strange to non-strange B meson production at 7,8 and 13 TeV.

Source code:LHCB_2019_I1760257.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/UnstableParticles.hh"

namespace Rivet {

/// @brief strange fraction at 7,8,13 TeV class LHCB_2019_I1760257 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(LHCB_2019_I1760257);


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

/// Book histograms and initialise projections before the run
void init() {
  // projection
  declare(UnstableParticles(), "UFS");

  for (double eVal : allowedEnergies()) {
    const int en(eVal + 0.5);
    if (isCompatibleWithSqrtS(eVal)) {
      if (en == 7000)
        _sqs = 0;
      else if (en == 8000)
        _sqs = 1;
      else
        _sqs = 2;
    }
  }
  raiseBeamErrorIf(_sqs < 0);
  //histograms
  for (size_t ix = 0; ix < 2; ++ix) {
    book(_c_B[ix], "TMP/c_B_" + toString(ix + 1), refData<YODA::BinnedEstimate<string>>(1, 1, 1));
    for (size_t iy = 0; iy < 3; ++iy) {
      book(_h_pT[ix][iy], "TMP/h_pT_" + toString(ix + 1) + "_" + toString(iy + 1), refData(5, 1, 1 + iy));
      book(_h_pL[ix][iy], "TMP/h_pL_" + toString(ix + 1) + "_" + toString(iy + 1), refData(3, 1, 1 + iy));
    }
    for (size_t iy = 0; iy < 5; ++iy) {
      book(_h_kin[ix][iy], "TMP/h_kin_" + toString(ix + 1) + "_" + toString(iy + 1),
           refData(4, 1, 1 + iy));
    }
  }
}


/// Perform the per-event analysis
void analyze(const Event& event) {
  if (_edges.empty()) _edges = _c_B[0]->xEdges();
  for (const Particle& p :
       apply<UnstableParticles>(event, "UFS").particles(Cuts::abspid == 521 or Cuts::abspid == 531)) {
    // kinematic region
    // rapidity cuts
    double y = p.rapidity(), eta = p.eta();
    if (y < 2. || y > 4.5 || eta < 2. || eta > 6.5) continue;
    // momentum cuts
    double pT = p.perp() / GeV, pL = p.momentum().z() / GeV, pTot = p.momentum().p3().mod() / GeV;
    if (pT < 0.5 || pT > 40. || pTot < 20. || pTot > 700. || pL < 20. || pL > 700.) continue;
    // type of meson
    unsigned int imeson = (p.abspid() % 100) / 10 - 2;
    _c_B[imeson]->fill(_edges[_sqs]);
    if (_sqs == 2) _c_B[imeson]->fill(_edges[3]);
    _h_pT[imeson][_sqs]->fill(pT);
    if (pL < 75.)
      _h_pL[imeson][0]->fill(pT);
    else if (pL < 125.)
      _h_pL[imeson][1]->fill(pT);
    else if (pL < 700.)
      _h_pL[imeson][2]->fill(pT);
    _h_kin[imeson][0]->fill(pTot);
    _h_kin[imeson][1]->fill(pL);
    _h_kin[imeson][2]->fill(pT);
    _h_kin[imeson][3]->fill(eta);
    _h_kin[imeson][4]->fill(y);
  }
}


/// Normalise histograms etc., after the run
void finalize() {
  // ratio of branching ratios from PDSG 2020
  const double brRatio = 1.08e-3 / 1.02e-3;
  for (size_t iy = 0; iy < 5; ++iy) {
    Estimate1DPtr tmp;
    book(tmp, 4, 1, iy + 1);
    divide(_h_kin[1][iy], _h_kin[0][iy], tmp);
    tmp->scale(brRatio);
    if (iy >= 3) continue;
    book(tmp, 3, 1, iy + 1);
    divide(_h_pL[1][iy], _h_pL[0][iy], tmp);
    tmp->scale(brRatio);
    book(tmp, 5, 1, 1 + iy);
    divide(_h_pT[1][iy], _h_pT[0][iy], tmp);
    tmp->scale(brRatio);
  }
  // ratio
  BinnedEstimatePtr<string> ratio;
  book(ratio, 1, 1, 1);
  divide(_c_B[1], _c_B[0], ratio);
  ratio->scale(brRatio);
}

/// @}


/// @name Histograms
/// @{
int _sqs = -1;
vector<string> _edges;
BinnedHistoPtr<string> _c_B[2];
Histo1DPtr _h_pL[2][3], _h_kin[2][5], _h_pT[2][3];
/// @}

};

RIVET_DECLARE_PLUGIN(LHCB_2019_I1760257);

} ```