Rivet analyses

title: LHCB_2018_I1674916

Prompt $D_s+/D_s^-$ Asymmetry at 7 and 8 TeV

Experiment: LHCB (LHC)

Inspire ID: 1674916

Status: VALIDATED

Authors: - Peter Richardson

References: - JHEP 08 (2018) 008, 2018

Beams: p+ p+

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

Run details: - D_s production

Measurement of the production asymmetry for prompt $D_s+/D_s^-$ at 7 and 8 TeV by LHCb.

Source code:LHCB_2018_I1674916.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/FinalState.hh"

include "Rivet/Projections/UnstableParticles.hh"

namespace Rivet {

/// @brief D_s asymmetry class LHCB_2018_I1674916 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(LHCB_2018_I1674916);


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

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

  for (double eVal : allowedEnergies()) {
    const int en = int(eVal + 0.5);
    if (isCompatibleWithSqrtS(eVal)) _sqs = en;

    for (size_t ix = 0; ix < 2; ++ix) {
      book(_h[en + ix], {2., 3., 3.5, 4.5});
      for (auto& b : _h[en + ix]->bins()) {
        book(b, "TMP/h_" + toString(ix + 1) + "_" + toString(b.index()) + "_" + toString(en),
             refData(2, 1, b.index()));
      }
    }
  }
  raiseBeamErrorIf(_sqs == 0);
}


/// Perform the per-event analysis
void analyze(const Event& event) {
  const UnstableParticles& ufs = apply<UnstableParticles>(event, "UFS");
  for (const Particle& p : ufs.particles(Cuts::abspid == 431)) {
    if (p.fromBottom()) continue;
    const double pT = p.perp();
    const double y = p.absrap();
    const bool anti = p.pid() < 0;
    _h[_sqs + anti]->fill(y, pT);
  }
}


/// Normalise histograms etc., after the run
void finalize() {

  for (double eVal : allowedEnergies()) {
    const int en = int(eVal + 0.5);
    int ih = 2 + (en == 8000);
    // asymmetry
    Estimate1DPtr tmp;
    for (const auto& b : _h[en + 0]->bins()) {
      book(tmp, ih, 1, b.index());
      asymm(b, _h[en + 1]->bin(b.index()), tmp);
    }
  }
}

/// @}


/// @name Histograms
/// @{
map<int, Histo1DGroupPtr> _h;
int _sqs = 0;
/// @}

};

RIVET_DECLARE_PLUGIN(LHCB_2018_I1674916);

} ```