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/Coll_ChEx [ Modules ]

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PURPOSE

Implement a + b -> X elastic processes/reactions (for the HiEnergy part) by doing a charge exchange.


Coll_Elastic/DoColl_ChEx [ Subroutines ]

[ Top ] [ Coll_Elastic ] [ Subroutines ]

NAME

subroutine DoColl_ChEx(inPart,outPart,flagOK,sqrtS,pcm,beta,AngDist)

PURPOSE

Perform a collision of particles given in "inPart" with energy "sqrtS" and return outgoing particles in "outPart".

"pcm" and "beta" are vectors used for Boost and Rotation of the event.

if "flagOK" is false, no event happened, the output in "outPart" should be neglected!

Different angular (tSlope) distributions are possible:

  • isotropic
  • tSlope_EL_pbarp(sqrts) --- for pbar p elastic scattering from L.A. Kondratyuk and M.G. Sapozhnikov, Sov. J. Nucl. Phys. 46, 56 (1987).
  • tSlope_CEX_pbarp(sqrts) --- for pbar p --> nbar n charge exchange parameterization of available HEP data at plab=0.7-35 GeV/c by A.L.

INPUTS

  • type(particle),dimension(:) :: inPart -- incoming particles
  • real :: sqrtS -- energy of ollision
  • real, dimension(0:3) :: pcm -- boost-vector
  • real, dimension(1:3) :: beta -- boost vector
  • integer, :: AngDist -- angular distribution

OUTPUT

  • type(particle),dimension(:) :: outPart ! outgoing particles
  • logical :: flagOK ! event okay ?

NOTES

cf. DoColl_Pythia

in order to understand the meaning of "pcm" and "beta": The (Pythia-)event is done in the restframe of the two given particles. Then a call to PYROBO according

       phi = atan2(pcm(2),pcm(1))
       theta = atan2(sqrt(pcm(1)**2+pcm(2)**2),pcm(3))
       call PYROBO(1,N, theta,phi, beta(1),beta(2),beta(3))

is performed in order to transform the system into the desired (Lab-) system.