Rivet analyses

title: LHCB_2022_I1960979

Mass distributions in $B_c^+\to J/\psi+$ $\pi^+\pi^+\pi^-$, $K^+K^-\pi^+$ and $K^+\pi^+\pi^-$

Experiment: LHCB (LHC)

Inspire ID: 1960979

Status: VALIDATED NOHEPDATA

Authors: - Peter Richardson

References: - JHEP 01 (2022) 065

Beams: * *

Beam energies: ANY

Run details: - Any process producing B_c+, originally pp

Mass distributions in $B_c^+\to J/\psi+$ $\pi^+\pi^+\pi^-$, $K^+K^-\pi^+$ and $K^+\pi^+\pi^-$. The data were read from the plots in the paper and may not be corrected for efficiency and acceptance.

Source code:LHCB_2022_I1960979.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/DecayedParticles.hh"

include "Rivet/Projections/UnstableParticles.hh"

namespace Rivet {

/// @brief B_c - > jpsi + 3 charged hadrons class LHCB_2022_I1960979 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(LHCB_2022_I1960979);


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

/// Book histograms and initialise projections before the run
void init() {
  UnstableParticles ufs = UnstableParticles(Cuts::abspid == 541);
  declare(ufs, "UFS");
  DecayedParticles BC(ufs);
  BC.addStable(PID::PI0);
  BC.addStable(PID::K0S);
  BC.addStable(PID::JPSI);
  declare(BC, "BC");
  for (unsigned int ix = 0; ix < 4; ++ix) {
    for (unsigned int iy = 0; iy < 2; ++iy) {
      if (iy == 1 && ix > 1) continue;
      book(_h[ix][iy], 1 + ix, 1, 1 + iy);
    }
  }
}


/// Perform the per-event analysis
void analyze(const Event& event) {
  static const map<PdgId, unsigned int>& mode1 = {{443, 1}, {211, 2}, {-211, 1}};
  static const map<PdgId, unsigned int>& mode1CC = {{443, 1}, {-211, 2}, {211, 1}};
  static const map<PdgId, unsigned int>& mode2 = {{443, 1}, {321, 1}, {-321, 1}, {211, 1}};
  static const map<PdgId, unsigned int>& mode2CC = {{443, 1}, {321, 1}, {-321, 1}, {-211, 1}};
  static const map<PdgId, unsigned int>& mode3 = {{443, 1}, {211, 1}, {-211, 1}, {321, 1}};
  static const map<PdgId, unsigned int>& mode3CC = {{443, 1}, {211, 1}, {-211, 1}, {-321, 1}};
  static const map<PdgId, unsigned int>& mode4 = {{443, 1}, {321, 2}, {-321, 1}};
  static const map<PdgId, unsigned int>& mode4CC = {{443, 1}, {321, 1}, {-321, 2}};
  DecayedParticles BC = apply<DecayedParticles>(event, "BC");
  // loop over particles
  for (unsigned int ix = 0; ix < BC.decaying().size(); ++ix) {
    int sign = BC.decaying()[ix].pid() / BC.decaying()[ix].abspid();
    if ((sign == 1 && BC.modeMatches(ix, 4, mode1)) || (sign == -1 && BC.modeMatches(ix, 4, mode1CC))) {
      const Particle& pim = BC.decayProducts()[ix].at(-sign * 211)[0];
      const Particles& pip = BC.decayProducts()[ix].at(sign * 211);
      _h[0][0]->fill((pim.momentum() + pip[0].momentum() + pip[1].momentum()).mass());
      _h[0][1]->fill((pim.momentum() + pip[0].momentum()).mass());
      _h[0][1]->fill((pim.momentum() + pip[1].momentum()).mass());
    }
    else if ((sign == 1 && BC.modeMatches(ix, 4, mode2))
             || (sign == -1 && BC.modeMatches(ix, 4, mode2CC))) {
      const Particle& Kp = BC.decayProducts()[ix].at(sign * 321)[0];
      const Particle& Km = BC.decayProducts()[ix].at(-sign * 321)[0];
      const Particle& pip = BC.decayProducts()[ix].at(sign * 211)[0];
      _h[1][0]->fill((Km.momentum() + pip.momentum()).mass());
      _h[1][1]->fill((Km.momentum() + Kp.momentum()).mass());
    }
    else if ((sign == 1 && BC.modeMatches(ix, 4, mode3))
             || (sign == -1 && BC.modeMatches(ix, 4, mode3CC))) {
      const Particle& pim = BC.decayProducts()[ix].at(-sign * 211)[0];
      const Particle& Kp = BC.decayProducts()[ix].at(sign * 321)[0];
      _h[2][0]->fill((Kp.momentum() + pim.momentum()).mass());
    }
    else if ((sign == 1 && BC.modeMatches(ix, 4, mode4))
             || (sign == -1 && BC.modeMatches(ix, 4, mode4CC))) {
      const Particle& Km = BC.decayProducts()[ix].at(-sign * 321)[0];
      const Particles& Kp = BC.decayProducts()[ix].at(sign * 321);
      _h[3][0]->fill((Kp[0].momentum() + Km.momentum()).mass());
      _h[3][0]->fill((Kp[1].momentum() + Km.momentum()).mass());
    }
  }
}


/// Normalise histograms etc., after the run
void finalize() {
  for (unsigned int ix = 0; ix < 3; ++ix) {
    for (unsigned int iy = 0; iy < 2; ++iy) {
      if (iy == 1 && ix > 1) continue;
      normalize(_h[ix][iy], 1., false);
    }
  }
}

/// @}


/// @name Histograms
/// @{
Histo1DPtr _h[4][2];
/// @}

};

RIVET_DECLARE_PLUGIN(LHCB_2022_I1960979);

} ```