EvtTauola.cc

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//--------------------------------------------------------------------------
//
// Environment:
//      This software is part of models developed at BES collaboration
//      based on the EvtGen framework.  If you use all or part
//      of it, please give an appropriate acknowledgement.
//
// Copyright Information: See EvtGen/BesCopyright
//      Copyright (A) 2006      Ping Rong-Gang
//
// Module: EvtTauola.cc
//         the necessary file: tauola2.4.F
//
// Description: interface to the tauola package
//
// Modification history:
//
//   Ping R.-G.    2008-07-13       Module created
//
//------------------------------------------------------------------------
//
#include "EvtTauola.hh"
#include "../EvtGenBase/EvtDecayBase.hh"
#include "../EvtGenBase/EvtDecayTable.hh"
#include "../EvtGenBase/EvtId.hh"
#include "../EvtGenBase/EvtPDL.hh"
#include "../EvtGenBase/EvtParticle.hh"
#include "../EvtGenBase/EvtPatches.hh"
#include "../EvtGenBase/EvtReport.hh"
#include "../EvtGenBase/EvtStringParticle.hh"
#include <fstream>
#include <iomanip>
#include <iostream>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <string>
#include <unistd.h>
using std::endl;
using std::fstream;
using std::ios;
using std::ofstream;
using std::resetiosflags;
using std::setiosflags;
using std::setw;
 
int              EvtTauola::ntauoladecays = 0;
EvtDecayBasePtr* EvtTauola::tauoladecays  = 0;
int              EvtTauola::ntable        = 0;
 
int          EvtTauola::ncommand = 0;
int          EvtTauola::lcommand = 0;
std::string* EvtTauola::commands = 0;
 
extern "C" {
extern void dectes_( int*, int*, int*, int*, int*, double*, double*, double*, double* );
}
 
EvtTauola::EvtTauola() {}
 
EvtTauola::~EvtTauola() {
 
  int i;
 
  // the deletion of commands is really uggly!
 
  if ( ntauoladecays == 0 )
  {
    delete[] commands;
    commands = 0;
    return;
  }
 
  for ( i = 0; i < ntauoladecays; i++ )
  {
    if ( tauoladecays[i] == this )
    {
      tauoladecays[i] = tauoladecays[ntauoladecays - 1];
      ntauoladecays--;
      if ( ntauoladecays == 0 )
      {
        delete[] commands;
        commands = 0;
      }
      return;
    }
  }
 
  report( ERROR, "EvtGen" ) << "Error in destroying Tauola model!" << endl;
}
 
void EvtTauola::getName( std::string& model_name ) { model_name = "TAUOLA"; }
 
EvtDecayBase* EvtTauola::clone() { return new EvtTauola; }
 
void EvtTauola::initProbMax() { noProbMax(); }
 
void EvtTauola::init() {
 
  //  checkNArg(1);
 
  if ( getParentId().isAlias() )
  {
 
    report( ERROR, "EvtGen" ) << "EvtTauola finds that you are decaying the" << endl
                              << " aliased particle " << EvtPDL::name( getParentId() ).c_str()
                              << " with the Tauola model" << endl
                              << " this does not work, please modify decay table." << endl;
    report( ERROR, "EvtGen" ) << "Will terminate execution!" << endl;
    ::abort();
  }
 
  store( this );
  // std::cout<<"Tauola initialization"<<std::endl;
}
 
std::string EvtTauola::commandName() { return std::string( "TauolaPar" ); }
 
void EvtTauola::command( std::string cmd ) {
 
  if ( ncommand == lcommand )
  {
 
    lcommand = 10 + 2 * lcommand;
 
    std::string* newcommands = new std::string[lcommand];
 
    int i;
 
    for ( i = 0; i < ncommand; i++ ) { newcommands[i] = commands[i]; }
 
    delete[] commands;
 
    commands = newcommands;
  }
 
  commands[ncommand] = cmd;
 
  ncommand++;
}
 
void EvtTauola::decay( EvtParticle* p ) {
 
  static int iniflag = 0;
 
  static EvtId STRNG = EvtPDL::getId( "string" );
 
  int istdheppar = EvtPDL::getStdHep( p->getId() );
 
  /*
    if (pycomp_(&istdheppar)==0){
      report(ERROR,"EvtGen") << "Tauola can not decay:"
        <<EvtPDL::name(p->getId()).c_str()<<endl;
      return;
    }
  */
 
  EvtVector4R p4[20];
 
  int        i, more;
  int        idtau = EvtPDL::getStdHep( p->getId() );
  int        ndaugjs;
  static int kf[20];
  EvtId      evtnumstable[20], evtnumparton[20];
  int        stableindex[20], partonindex[20];
  int        numstable;
  int        numparton;
  static int km[20];
  EvtId      type[MAX_DAUG];
 
  static double px[20], py[20], pz[20], e[20];
 
  //  std::cout<<"cc: inifag,idtau,taup,polt"<<iniflag<<"; "<<idtau<<"; "<<taup[0]<<";
  //  "<<polt[3]<<endl;
  if ( iniflag == 0 ) dectes_( &iniflag, &idtau, &ndaugjs, kf, km, px, py, pz, e );
  // std::cout<<"Tauola initialized"<<endl;
  if ( p->getNDaug() != 0 ) { p->deleteDaughters( true ); }
 
  int count = 0;
 
  do {
    // report(INFO,"EvtGen") << "calling tauola " << idtau<< " " << mp <<endl;
    iniflag = iniflag + 1; // to count the event number
    dectes_( &iniflag, &idtau, &ndaugjs, kf, km, px, py, pz, e );
 
    numstable = 0;
    numparton = 0;
    //    report(INFO,"EvtGen") << "found some daughters " << ndaugjs << endl;
    for ( i = 0; i < ndaugjs; i++ )
    {
      // std::cout<<"ndaugjs,kf,km,px,py,pz,e: "<<i<<", "<<km[i]<<", "<<kf[i]<<", "<<px[i]<<"
      // ,"<<py[i]<<", "<<pz[i]<<", "<<e[i]<<std::endl; //for debugging
 
      if ( EvtPDL::evtIdFromStdHep( kf[i] ) == EvtId( -1, -1 ) )
      {
        report( ERROR, "EvtGen" ) << "Tauola returned particle:" << kf[i] << endl;
        report( ERROR, "EvtGen" ) << "This can not be translated to evt number" << endl;
        report( ERROR, "EvtGen" ) << "and the decay will be rejected!" << endl;
        report( ERROR, "EvtGen" ) << "The decay was of particle:" << idtau << endl;
      }
 
      // sort out the partons
      if ( abs( kf[i] ) <= 6 || kf[i] == 21 )
      {
        partonindex[numparton]  = i;
        evtnumparton[numparton] = EvtPDL::evtIdFromStdHep( kf[i] );
        numparton++;
      }
      else
      {
        stableindex[numstable]  = i;
        evtnumstable[numstable] = EvtPDL::evtIdFromStdHep( kf[i] );
        numstable++;
      }
 
      // have to protect against negative mass^2 for massless particles
      // i.e. neutrinos and photons.
      // this is uggly but I need to fix it right now....
 
      if ( px[i] * px[i] + py[i] * py[i] + pz[i] * pz[i] >= e[i] * e[i] )
      { e[i] = sqrt( px[i] * px[i] + py[i] * py[i] + pz[i] * pz[i] ) + 0.0000000001; }
 
      p4[i].set( e[i], px[i], py[i], pz[i] );
    }
 
    int channel = EvtDecayTable::inChannelList( p->getId(), numstable, evtnumstable );
 
    more = ( channel != -1 );
 
    count++;
 
  } while ( more && ( count < 10000 ) );
 
  if ( count > 9999 )
  {
    report( INFO, "EvtGen" ) << "Too many loops in EvtTauola!!!" << endl;
    report( INFO, "EvtGen" ) << "Parent:" << EvtPDL::name( getParentId() ).c_str() << endl;
    for ( i = 0; i < numstable; i++ )
    {
      report( INFO, "EvtGen" ) << "Daug(" << i << ")"
                               << EvtPDL::name( evtnumstable[i] ).c_str() << endl;
    }
  }
 
  if ( numparton == 0 )
  {
 
    p->makeDaughters( numstable, evtnumstable );
    int ndaugFound = 0;
    for ( i = 0; i < numstable; i++ )
    {
      p->getDaug( i )->init( evtnumstable[i], p4[stableindex[i]] );
      ndaugFound++;
    }
    if ( ndaugFound == 0 )
    {
      report( ERROR, "EvtGen" ) << "Tauola has failed to do a decay ";
      report( ERROR, "EvtGen" ) << EvtPDL::name( p->getId() ).c_str() << " " << p->mass()
                                << endl;
      assert( 0 );
    }
 
    fixPolarizations( p );
 
    return;
  }
  else
  {
 
    // have partons in TAUOLA
 
    EvtVector4R p4string( 0.0, 0.0, 0.0, 0.0 );
 
    for ( i = 0; i < numparton; i++ ) { p4string += p4[partonindex[i]]; }
 
    int nprimary = 1;
    type[0]      = STRNG;
    for ( i = 0; i < numstable; i++ )
    {
      if ( km[stableindex[i]] == 0 ) { type[nprimary++] = evtnumstable[i]; }
    }
 
    p->makeDaughters( nprimary, type );
 
    p->getDaug( 0 )->init( STRNG, p4string );
 
    EvtVector4R p4partons[10];
 
    for ( i = 0; i < numparton; i++ ) { p4partons[i] = p4[partonindex[i]]; }
 
    ( (EvtStringParticle*)p->getDaug( 0 ) )->initPartons( numparton, p4partons, evtnumparton );
 
    nprimary = 1;
 
    for ( i = 0; i < numstable; i++ )
    {
 
      if ( km[stableindex[i]] == 0 )
      { p->getDaug( nprimary++ )->init( evtnumstable[i], p4[stableindex[i]] ); }
    }
 
    int nsecond = 0;
    for ( i = 0; i < numstable; i++ )
    {
      if ( km[stableindex[i]] != 0 ) { type[nsecond++] = evtnumstable[i]; }
    }
 
    p->getDaug( 0 )->makeDaughters( nsecond, type );
 
    EvtVector4R p4stringboost( p4string.get( 0 ), -p4string.get( 1 ), -p4string.get( 2 ),
                               -p4string.get( 3 ) );
 
    nsecond = 0;
    for ( i = 0; i < numstable; i++ )
    {
      if ( km[stableindex[i]] != 0 )
      {
        p4[stableindex[i]] = boostTo( p4[stableindex[i]], p4stringboost );
        p->getDaug( 0 )->getDaug( nsecond )->init( evtnumstable[i], p4[stableindex[i]] );
        p->getDaug( 0 )->getDaug( nsecond )->setDiagonalSpinDensity();
        p->getDaug( 0 )->getDaug( nsecond )->decay();
        nsecond++;
      }
    }
 
    if ( nsecond == 0 )
    {
      report( ERROR, "EvtGen" ) << "Jetset has failed to do a decay ";
      report( ERROR, "EvtGen" ) << EvtPDL::name( p->getId() ).c_str() << " " << p->mass()
                                << endl;
      assert( 0 );
    }
 
    fixPolarizations( p );
 
    return;
  }
}
 
void EvtTauola::fixPolarizations( EvtParticle* p ) {
 
  // special case for now to handle the tau polarization
 
  int ndaug = p->getNDaug();
 
  int i;
 
  //  static EvtId tau=EvtPDL::getId("tau-");
  static EvtId tau = getParentId();
 
  for ( i = 0; i < ndaug; i++ )
  {
    if ( p->getDaug( i )->getId() == tau )
    {
 
      EvtSpinDensity rho;
 
      rho.SetDim( 2 );
      rho.Set( 0, 0, 1.0 );
      rho.Set( 0, 1, 0.0 );
 
      rho.Set( 1, 0, 0.0 );
      rho.Set( 1, 1, 1.0 );
 
      EvtVector4R p4Psi = p->getDaug( i )->getP4();
 
      double alpha = atan2( p4Psi.get( 2 ), p4Psi.get( 1 ) );
      double beta  = acos( p4Psi.get( 3 ) / p4Psi.d3mag() );
 
      p->getDaug( i )->setSpinDensityForwardHelicityBasis( rho, alpha, beta, 0.0 );
      setDaughterSpinDensity( i );
    }
  }
}
 
void EvtTauola::store( EvtDecayBase* jsdecay ) {
 
  if ( ntauoladecays == ntable )
  {
 
    EvtDecayBasePtr* newtauoladecays = new EvtDecayBasePtr[2 * ntable + 10];
    int              i;
    for ( i = 0; i < ntable; i++ ) { newtauoladecays[i] = tauoladecays[i]; }
    ntable = 2 * ntable + 10;
    delete[] tauoladecays;
    tauoladecays = newtauoladecays;
  }
 
  tauoladecays[ntauoladecays++] = jsdecay;
}