P4BaseEEtaPhiM Class Reference

P4BaseEEtaPhiM is a base class for classes with 4-momentum behavior, for which E, eta, phi and M are natural parameters, which is typically the case for a calorimeter object. More...

#include <P4BaseEEtaPhiM.h>

Inheritance diagram for P4BaseEEtaPhiM:

Collaboration diagram for P4BaseEEtaPhiM:

Public Member Functions
virtual	~P4BaseEEtaPhiM ()
	virtual destructor needed for inheritance
double	px () const
	{@ a la I4Momentum -like interface
double	py () const
double	pz () const
virtual double	m () const =0
double	m2 () const
double	rapidity () const
double	p () const
double	p2 () const
virtual double	eta () const =0
virtual double	phi () const =0
virtual double	e () const =0
double	et () const
double	pt () const
double	iPt () const
double	sinPhi () const
double	cosPhi () const
double	tanTh () const
double	cosTh () const
double	sinTh () const
double	cotTh () const
CLHEP::HepLorentzVector	hlv () const
std::ostream &	dump (std::ostream &out) const
	Print I4Momentum content.

Detailed Description

P4BaseEEtaPhiM is a base class for classes with 4-momentum behavior, for which E, eta, phi and M are natural parameters, which is typically the case for a calorimeter object.

Any class deriving from it should implement e(), eta(), phi(), m().

Author

David Rousseau rouss.nosp@m.eau@.nosp@m.lal.i.nosp@m.n2p3.nosp@m..fr

Definition at line 32 of file P4BaseEEtaPhiM.h.

Constructor & Destructor Documentation

~P4BaseEEtaPhiM()

P4BaseEEtaPhiM::~P4BaseEEtaPhiM ( )

inlinevirtual

virtual destructor needed for inheritance

Definition at line 87 of file P4BaseEEtaPhiM.h.

{}

Member Function Documentation

cosPhi()

double P4BaseEEtaPhiM::cosPhi ( ) const

inline

Definition at line 166 of file P4BaseEEtaPhiM.h.

{
 return std::cos(this->phi());
}

cosTh()

double P4BaseEEtaPhiM::cosTh ( ) const

inline

Definition at line 187 of file P4BaseEEtaPhiM.h.

{ 
  return std::tanh(this->eta());
}

cotTh()

double P4BaseEEtaPhiM::cotTh ( ) const

inline

Definition at line 204 of file P4BaseEEtaPhiM.h.

{ 
  return std::sinh(this->eta());
}

dump()

std::ostream & P4BaseEEtaPhiM::dump ( std::ostream & out ) const

inline

Print I4Momentum content.

Definition at line 231 of file P4BaseEEtaPhiM.h.

{
  std::stringstream s;
  s << "[e,eta,phi,m] ="
    << std::right << std::scientific << std::setprecision(8) 
    << std::setw(16) << this->e()
    << std::setw(16) << this->eta()
    << std::setw(16) << this->phi()
    << std::setw(16) << this->m();
 
  out << s.str();
  return out;
 
}

e()

virtual double P4BaseEEtaPhiM::e ( ) const

pure virtual

Implemented in P4Impl< P4ImplEEtaPhiM >, and P4ImplEEtaPhiM.

et()

double P4BaseEEtaPhiM::et ( ) const

inline

Definition at line 144 of file P4BaseEEtaPhiM.h.

{
  return this->e()*this->sinTh();
}

eta()

virtual double P4BaseEEtaPhiM::eta ( ) const

pure virtual

Implemented in P4Impl< P4ImplEEtaPhiM >, and P4ImplEEtaPhiM.

hlv()

CLHEP::HepLorentzVector P4BaseEEtaPhiM::hlv ( ) const

inline

Definition at line 209 of file P4BaseEEtaPhiM.h.

{
  //minimize the number of calculation and dereference
  const double theE = this->e();
  const double theCosTh = this->cosTh();  
  
  // DR from Frank Paige
  // negative energy point in opposite direction
  // BUT Eta and Phi still the same
  //  double theP=theE;
  
  const double theP = this->p();
  
  const double theSinTh = std::sqrt(1.-theCosTh*theCosTh);
  const double thePt = theP*theSinTh;
  const double thePx = thePt*this->cosPhi();
  const double thePy = thePt*this->sinPhi();
  const double thePz = theP*theCosTh;  
  
  return CLHEP::HepLorentzVector(thePx,thePy,thePz,theE);
}

iPt()

double P4BaseEEtaPhiM::iPt ( ) const

inline

Definition at line 161 of file P4BaseEEtaPhiM.h.

{ 
  return 1./this->pt();
}

m()

virtual double P4BaseEEtaPhiM::m ( ) const

pure virtual

Implemented in P4Impl< P4ImplEEtaPhiM >, and P4ImplEEtaPhiM.

m2()

double P4BaseEEtaPhiM::m2 ( ) const

inline

Definition at line 105 of file P4BaseEEtaPhiM.h.

{ 
  const double mass = this->m();
  return mass*mass;
}

p()

double P4BaseEEtaPhiM::p ( ) const

inline

Definition at line 111 of file P4BaseEEtaPhiM.h.

{ 
  const double theM=this->m();
  const double theE=this->e();
  //  if (theM==0.) return theE ;
  //    else return sqrt(theE*theE-theM*theM); 
  //DR from Frank Paige
  // if negative energy point in the opposite direction
  // BUT eta and phi still the same !!!
  if (theM==0.) {
    return theE;
  } else {
    double eSign = (theE >= 0.) ? +1. : -1.;
    return eSign*std::sqrt(theE*theE-theM*theM); 
  }
 
}

p2()

double P4BaseEEtaPhiM::p2 ( ) const

inline

This p2() implementaion is derived from the (somewhat unusual) Frank Paige implementation used to calculate p() above. What we do is look at what would happen if we were to square the answer returned by Frank's algorithm:

(1) The "eSign" would square to +1 and disappear, (2) The sqrt would disappear leaving theE*theE-theM*theM (3) In the event that theM==0, this theE*theE would indeed still equal theE*theE-theM*theM, so we simply return this quantity.

Definition at line 129 of file P4BaseEEtaPhiM.h.

{ 
  const double mass = this->m();
  const double ene  = this->e();
  
  return ene*ene - mass*mass;
}

phi()

virtual double P4BaseEEtaPhiM::phi ( ) const

pure virtual

Implemented in P4Impl< P4ImplEEtaPhiM >, and P4ImplEEtaPhiM.

pt()

double P4BaseEEtaPhiM::pt ( void ) const

inline

Definition at line 156 of file P4BaseEEtaPhiM.h.

{
  return this->p()*this->sinTh();
}

px()

double P4BaseEEtaPhiM::px ( ) const

inline

{@ a la I4Momentum -like interface

Definition at line 90 of file P4BaseEEtaPhiM.h.

{ 
  return this->pt()*cos(this->phi());
}

py()

double P4BaseEEtaPhiM::py ( ) const

inline

Definition at line 95 of file P4BaseEEtaPhiM.h.

{ 
  return this->pt()*sin(this->phi());
}

pz()

double P4BaseEEtaPhiM::pz ( ) const

inline

Definition at line 100 of file P4BaseEEtaPhiM.h.

{ 
  return this->p()*this->cosTh();
}

rapidity()

double P4BaseEEtaPhiM::rapidity ( ) const

inline

Definition at line 149 of file P4BaseEEtaPhiM.h.

  {
    const double theE=this->e();
    const double thePz=this->pz();
    return 0.5*std::log((theE+thePz)/(theE-thePz));
   }

sinPhi()

double P4BaseEEtaPhiM::sinPhi ( ) const

inline

Definition at line 171 of file P4BaseEEtaPhiM.h.

{ 
  return std::sin(this->phi());
}

sinTh()

double P4BaseEEtaPhiM::sinTh ( ) const

inline

Definition at line 192 of file P4BaseEEtaPhiM.h.

{ 
  // avoid numeric overflow if very large eta
 
  double aEta=std::abs(this->eta());
  if ( aEta>710) {
    aEta=710;
  }
 
  return 1./std::cosh(aEta);
}

tanTh()

double P4BaseEEtaPhiM::tanTh ( ) const

inline

Definition at line 177 of file P4BaseEEtaPhiM.h.

{ 
  double theEta=this->eta();
  if ( std::abs(theEta)>710) {
    theEta=theEta>0 ? 710 : -710;
    return 1./std::sinh(theEta);
  }
  return 1./this->cotTh();
}

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The documentation for this class was generated from the following file:

• P4BaseEEtaPhiM.h