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CellSmearer.cxx

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// CellSmearer.cxx
//
// Implementation of the Cell Smearer class
//
// Only the smear() method is overridden
// Based on JetSmearer, lowlumi, 0.1*0.1
//
// Authors: J.Couchman
//
//

#include "AtlfastAlgs/CellSmearer.h"
#include "AtlfastAlgs/PhotonSmearer.h"
#include <cmath>
#include <iostream>
#include "CLHEP/Vector/LorentzVector.h"
#include "CLHEP/Random/JamesRandom.h"
#include "CLHEP/Random/RandGauss.h"


namespace Atlfast {
  HepLorentzVector CellSmearer::smear (const HepLorentzVector& vec) {
//........................................................
//.....smear Cells energy
//........................................................
//     parametrizes smearing for hadronic energy deposition
//     parametrization from L. Poggioli
//     no pileup added

    float sigma=0.;
    HepLorentzVector smearedVec(vec);
    float aa, bb;
    float sqrtene = sqrt(vec.e());
    float abseta  = fabs(vec.pseudoRapidity());
    while(1) {
      aa=randGauss()->fire();
      bb=randGauss()->fire();
      if(abseta < m_BarrelForwardEta) sigma = aa*0.5/sqrtene + bb*0.03;
      else            sigma = aa*1.0/sqrtene + bb*0.07;
      if(1.+sigma > .0) break;
    }
    smearedVec.setPx(vec.px()*(1.0+sigma));
    smearedVec.setPy(vec.py()*(1.0+sigma));
    smearedVec.setPz(vec.pz()*(1.0+sigma));
    smearedVec.setE(vec.e()*(1.0+sigma));
    return smearedVec;
    
  }

}//end of namespace bracket

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