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/PythiaSpecFunc [ Modules ]

[ Top ] [ Modules ]

NAME

module PythiaSpecFunc

PURPOSE

Proper spectral functions for broad resonances in Pythia & Fritiof. We currently treat: 

  * vector mesons (rho, omega, phi)
  * Delta(1232)

PythiaSpecFunc/mediumAtCollision [ Global module-variables ]

[ Top ] [ PythiaSpecFunc ] [ Global module-variables ]

SOURCE

  type(medium), save :: mediumAtCollision

NOTES

Needed by VM_Mass, so one needs to set this parameter before PYTHIA/FRITIOF is called.

PythiaSpecFunc/Init_VM_Mass [ Subroutines ]

[ Top ] [ PythiaSpecFunc ] [ Subroutines ]

NAME

subroutine Init_VM_Mass(srts,position)

PURPOSE

Initialize the parameters srtFreeVMMass and mediumAtCollision before calling VM_Mass.

INPUTS

  • real :: srts -- sqrt(s) of collision
  • real,OPTIONAL :: position(1:3) -- place of collision

PythiaSpecFunc/VM_Mass [ Functions ]

[ Top ] [ PythiaSpecFunc ] [ Functions ]

NAME

real function VM_Mass(kfa,nReject)

PURPOSE

Select mass of vector mesons for Pythia/Fritiof (function pymass/ulmass) according to a relativistic Breit-Wigner with mass-dependent width.

Used for rho, omega and phi mesons.

INPUTS

  • integer :: kfa -- KF code of the particle

OUTPUT

  • function value returns the mass
  • integer, OPTIONAL :: nReject -- number of steps in rejection method

NOTES

  • Init_VM_Mass needs to be called before Pythia/Fritriof is called in order to set the medium at the position (THIS IS IMPORTANT!)
  • The mass selection is done in principle like in massass or assmass, but here we have improved the MC selection a little bit by dividing the mass region into slices.

PythiaSpecFunc/Delta_Mass [ Functions ]

[ Top ] [ PythiaSpecFunc ] [ Functions ]

NAME

real function Delta_Mass(nReject)

PURPOSE

Select mass of vector mesons for Pythia/Fritiof (function pymass/ulmass) according to a relativistic Breit-Wigner with mass-dependent width.

Used for Delta Resonances.

OUTPUT

  • function value returns the mass
  • integer, OPTIONAL :: nReject -- number of steps in rejection method

NOTES

  • This is important for dilepton simulations, where high-mass Deltas give a large contribution to the dilepton spectrum.
  • Treatment as in VM_Mass, but with slightly changed mass slices. (weight bwd is not always an increasing function with M!)

PythiaSpecFunc/VM_Mass_Full [ Functions ]

[ Top ] [ PythiaSpecFunc ] [ Functions ]

NAME

real function VM_Mass_Full(kfa,nReject)

PURPOSE

Select mass of vector mesons for Pythia/Fritiof (function pymass/ulmass) according to a relativistic Breit-Wigner with mass-dependent width.

Used for rho, omega and phi mesons.

This is the internal routine, which is called, if UseMassAssInfo is set false

INPUTS

  • integer :: kfa -- KF code of the particle

OUTPUT

  • function value returns the mass
  • integer, OPTIONAL :: nReject -- number of steps in rejection method

NOTES

  • Init_VM_Mass needs to be called before Pythia/Fritriof is called in order to set the medium at the position (THIS IS IMPORTANT!)
  • The mass selection is done in principle like in massass or assmass, but here we have improved the MC selection a little bit by dividing the mass region into slices.

PythiaSpecFunc/Delta_Mass_Full [ Functions ]

[ Top ] [ PythiaSpecFunc ] [ Functions ]

NAME

real function Delta_Mass_Full(nReject)

PURPOSE

Select mass of vector mesons for Pythia/Fritiof (function pymass/ulmass) according to a relativistic Breit-Wigner with mass-dependent width.

Used for Delta Resonances.

This is the internal routine, which is called, if UseMassAssInfo is set false

OUTPUT

  • function value returns the mass
  • integer, OPTIONAL :: nReject -- number of steps in rejection method

NOTES

  • This is important for dilepton simulations, where high-mass Deltas give a large contribution to the dilepton spectrum.
  • Treatment as in VM_Mass, but with slightly changed mass slices. (weight bwd is not always an increasing function with M!)