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Rivet analyses reference
BABAR_2012_I1185407
Mass distributions in $\tau^-\to2\pi^-\pi^+3\pi^0\nu_\tau$, $3\pi^-2\pi^+\nu_\tau$ and $3\pi^-2\pi^+\pi^0\nu_\tau$
Experiment: BABAR (PEP-II)
Inspire ID: 1185407
Status: VALIDATED NOHEPDATA
Authors:
References:
- Phys.Rev.D 86 (2012) 092010
Beams: * *
Beam energies: ANY
Run details:
- Any process producing tau leptons, originally e+e-
Measurement of mass distributions in $\tau^-\to2\pi^-\pi^+3\pi^0\nu_\tau$, $3\pi^-2\pi^+\nu_\tau$ and $3\pi^-2\pi^+\pi^0\nu_\tau$. The data were read from the plots in the paper and are not corrected, although the backgrounds given in the paper have been subtracted. The plots should therefore only be used for qualitative comparisons however the data is useful as there are not corrected distributions for this decay mode.
Source code:
BABAR_2012_I1185407.cc
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126 | // -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/FinalState.hh"
#include "Rivet/Projections/UnstableParticles.hh"
#include "Rivet/Projections/DecayedParticles.hh"
namespace Rivet {
/// @brief tau -> 5 and 5 pion final states
class BABAR_2012_I1185407 : public Analysis {
public:
/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(BABAR_2012_I1185407);
/// @name Analysis methods
/// @{
/// Book histograms and initialise projections before the run
void init() {
// Initialise and register projections
UnstableParticles ufs = UnstableParticles(Cuts::abspid==15);
declare(ufs, "UFS");
DecayedParticles TAU(ufs);
TAU.addStable(310);
TAU.addStable(111);
declare(TAU, "TAU");
// histogram
for(unsigned int ix=0;ix<4;++ix) {
book(_h_6pi[ix],3,1,1+ix);
if(ix>2) continue;
book(_h_3pi[ix],1,1,1+ix);
book(_h_5pi[ix],2,1,1+ix);
}
}
/// Perform the per-event analysis
void analyze(const Event& event) {
static const map<PdgId,unsigned int> & mode1 = { {-211,2}, { 211,1},{111,3},{ 16,1}};
static const map<PdgId,unsigned int> & mode1CC = { { 211,2}, {-211,1},{111,3},{-16,1}};
static const map<PdgId,unsigned int> & mode2 = { {-211,3}, { 211,2},{ 16,1}};
static const map<PdgId,unsigned int> & mode2CC = { { 211,3}, {-211,2},{-16,1}};
static const map<PdgId,unsigned int> & mode3 = { {-211,3}, { 211,2},{111,1},{ 16,1}};
static const map<PdgId,unsigned int> & mode3CC = { { 211,3}, {-211,2},{111,1},{-16,1}};
DecayedParticles TAU = apply<DecayedParticles>(event, "TAU");
// loop over particles
for(unsigned int ix=0;ix<TAU.decaying().size();++ix) {
int sign = TAU.decaying()[ix].pid()>0 ? 1 : -1;
int imode=-1;
if(TAU.modeMatches(ix,7,mode1 ) ||
TAU.modeMatches(ix,7,mode1CC)) imode = 0;
else if(TAU.modeMatches(ix,6,mode2 ) ||
TAU.modeMatches(ix,6,mode2CC)) imode = 1;
else if(TAU.modeMatches(ix,7,mode3 ) ||
TAU.modeMatches(ix,7,mode3CC)) imode = 2;
else continue;
const Particles & pip = TAU.decayProducts()[ix].at( 211*sign);
const Particles & pim = TAU.decayProducts()[ix].at(-211*sign);
FourMomentum ptotal;
for(unsigned int ix=0;ix<pim.size();++ix) ptotal +=pim[ix].momentum();
for(unsigned int ix=0;ix<pip.size();++ix) ptotal +=pip[ix].momentum();
if(imode==1) {
_h_5pi[2]->fill(ptotal.mass());
for(unsigned int ix=0;ix<pim.size();++ix) {
_h_5pi[1]->fill((ptotal-pim[ix].momentum()).mass());
for(unsigned int iy=0;iy<pip.size();++iy) {
_h_5pi[0]->fill((pim[ix].momentum()+pip[iy].momentum()).mass());
}
}
}
else {
const Particles & pi0 = TAU.decayProducts()[ix].at(111);
FourMomentum ppi0;
for(unsigned int ix=0;ix<pi0.size();++ix) ppi0 +=pi0[ix].momentum();
ptotal+=ppi0;
if(imode==0 ) {
_h_3pi[0]->fill(ppi0.mass());
_h_3pi[2]->fill(ptotal.mass());
for(unsigned int ix=0;ix<pim.size();++ix) {
for(unsigned int iy=0;iy<pi0.size();++iy) {
_h_3pi[1]->fill((pip[0].momentum()+pim[ix].momentum()+pi0[iy].momentum()).mass());
}
}
}
else {
_h_6pi[3]->fill(ptotal.mass());
for(unsigned int ix=0;ix<pim.size();++ix) {
_h_6pi[2]->fill((ptotal-pim[ix].momentum()).mass());
for(unsigned int iy=0;iy<pip.size();++iy) {
_h_6pi[0]->fill((pim[ix].momentum()+pip[iy].momentum()).mass());
_h_6pi[1]->fill((pim[ix].momentum()+pip[iy].momentum()+pi0[0].momentum()).mass());
}
}
}
}
}
}
/// Normalise histograms etc., after the run
void finalize() {
for(unsigned int ix=0;ix<4;++ix) {
normalize(_h_6pi[ix]);
if(ix>2) continue;
normalize(_h_3pi[ix]);
normalize(_h_5pi[ix]);
}
}
/// @}
/// @name Histograms
/// @{
Histo1DPtr _h_3pi[3],_h_5pi[3],_h_6pi[4];
/// @}
};
RIVET_DECLARE_PLUGIN(BABAR_2012_I1185407);
}
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