Line data    Source code

       1             : //--------------------------------------------------------------------------
       2             : //
       3             : // Environment:
       4             : //      This software is part of the EvtGen package developed jointly
       5             : //      for the BaBar and CLEO collaborations.  If you use all or part
       6             : //      of it, please give an appropriate acknowledgement.
       7             : //
       8             : // Module: EvtBtoXsgammaKagan.cc
       9             : //
      10             : // Description:
      11             : //       Routine to perform two-body B->Xs,gamma decays with a fixed hadronic 
      12             : //       mass. For spectrum measurements.
      13             : //       The input parameters are 1: the hadronic mass
      14             : // Modification history:
      15             : //
      16             : //      Jim Libby October 11 2002
      17             : //------------------------------------------------------------------------
      18             : //
      19             : #include "EvtGenBase/EvtPatches.hh"
      20             : 
      21             : #include <stdlib.h>
      22             : #include "EvtGenModels/EvtBtoXsgamma.hh"
      23             : #include "EvtGenModels/EvtBtoXsgammaFlatEnergy.hh"
      24             : #include "EvtGenBase/EvtRandom.hh"
      25             : #include "EvtGenBase/EvtReport.hh"
      26             : #include <fstream>
      27             : using std::endl;
      28             : using std::fstream;
      29             : 
      30           0 : EvtBtoXsgammaFlatEnergy::~EvtBtoXsgammaFlatEnergy(){
      31           0 : }
      32             : 
      33             : void EvtBtoXsgammaFlatEnergy::init(int nArg, double* args){
      34             : 
      35           0 :   if ((nArg) > 3 || (nArg > 1 && nArg <3)){
      36             :   
      37           0 :   report(Severity::Error,"EvtGen") << "EvtBtoXsgamma generator model "
      38           0 :                          << "EvtBtoXsgammaFlatEnergy expected " 
      39           0 :                          << "either 1(default config) or two arguments but found: "<<nArg<<endl;
      40           0 :   report(Severity::Error,"EvtGen") << "Will terminate execution!"<<endl;
      41           0 :     ::abort();  
      42             :   }
      43           0 :   _mB0=5.2794;  
      44             :   double mPi = 0.140;
      45             :   double mK = 0.494;
      46           0 :   if(nArg == 1){
      47           0 :     _eMin = 1.7;
      48             :     //Invariant mass of Xsd must be greater the m_pi+m_K leads to 
      49             :     //Egamma < (m_B**2-(m_pi+m_k)**2)/(2m_B)
      50           0 :     _eMax = (pow(_mB0,2)-pow(mPi+mK,2))/(2.0*_mB0); 
      51           0 :   }else{
      52           0 :     _eMin=args[1];
      53           0 :     _eMax=args[2];
      54             :   }
      55           0 :   if (_eMax>(pow(_mB0,2)-pow(mPi+mK,2))/(2.0*_mB0)){
      56           0 :     report(Severity::Error,"EvtGen") << "Emax greater than Kinematic limit" << endl;
      57           0 :     report(Severity::Error,"EvtGen") << "Reset to the kinematic limit" << endl;
      58           0 :     report(Severity::Error,"EvtGen") << "(m_B**2-(m_pi+m_k)**2)/(2m_B)" << endl;
      59           0 :     _eMax = (pow(_mB0,2)-pow(mPi+mK,2))/(2.0*_mB0);
      60           0 :   }
      61           0 :   _eRange=_eMax-_eMin;
      62           0 : }
      63             : 
      64             : double EvtBtoXsgammaFlatEnergy::GetMass( int /*Xscode*/ ){
      65             :   
      66           0 :   double eGamma = EvtRandom::Flat(_eRange)+_eMin;
      67           0 :   double mH = sqrt(pow(_mB0,2)-2.0*_mB0*eGamma); 
      68           0 :   return mH;
      69             : }
      70             :