Rivet analyses

title: BABAR_2012_I1081760

$\pi^+\pi^-$ mass distribution in $B^0\to\pi^+\pi^-K^{*0}$ decays

Experiment: BABAR (PEP-II)

Inspire ID: 1081760

Status: VALIDATED NOHEPDATA

Authors: - Peter Richardson

References: - Phys.Rev.D 85 (2012) 072005

Beams: * *

Beam energies: ANY

Run details: - Any process producing B0, originally Upsilon(4S) decays

Measurement of the $\pi^+\pi^-$ mass distribution in $B^0\to\pi^+\pi^-K^{*0}$ decays. The other distriubutions in the paper are designed solely to isolate various resonant components and are therefore not implemented.

Source code:BABAR_2012_I1081760.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/DecayedParticles.hh"

include "Rivet/Projections/UnstableParticles.hh"

namespace Rivet {

/// @brief B0 -> pi+ pi- K*0 class BABAR_2012_I1081760 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(BABAR_2012_I1081760);


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

/// Book histograms and initialise projections before the run
void init() {
  // projections
  UnstableParticles ufs = UnstableParticles(Cuts::abspid == 511);
  declare(ufs, "UFS");
  DecayedParticles B0(ufs);
  B0.addStable(313);
  B0.addStable(-313);
  declare(B0, "B0");
  // histogram
  book(_h, 1, 1, 1);
}


/// Perform the per-event analysis
void analyze(const Event& event) {
  static const map<PdgId, unsigned int>& mode = {{211, 1}, {-211, 1}, {313, 1}};
  static const map<PdgId, unsigned int>& modeCC = {{211, 1}, {-211, 1}, {-313, 1}};
  DecayedParticles B0 = apply<DecayedParticles>(event, "B0");
  for (unsigned int ix = 0; ix < B0.decaying().size(); ++ix) {
    int sign = 1;
    if (B0.decaying()[ix].pid() > 0 && B0.modeMatches(ix, 3, mode))
      sign = 1;
    else if (B0.decaying()[ix].pid() < 0 && B0.modeMatches(ix, 3, modeCC))
      sign = -1;
    else
      continue;
    const Particle& pip = B0.decayProducts()[ix].at(sign * 211)[0];
    const Particle& pim = B0.decayProducts()[ix].at(-sign * 211)[0];
    _h->fill((pip.momentum() + pim.momentum()).mass());
  }
}


/// Normalise histograms etc., after the run
void finalize() {
  normalize(_h, 1., false);
}

/// @}


/// @name Histograms
/// @{
Histo1DPtr _h;
/// @}

};

RIVET_DECLARE_PLUGIN(BABAR_2012_I1081760);

} ```