c2bdcy.f File Reference

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Functions/Subroutines
subroutine	c2bdcy (p, p1, p2)
subroutine	c2bdcp (p, p1, cst, p2)
subroutine	c2bdc0 (p, p1, p2)

Function/Subroutine Documentation

c2bdc0()

subroutine c2bdc0	(	type(ptcl)	p,
		type(ptcl)	p1,
		type(ptcl)	p2
	)

Definition at line 201 of file c2bdcy.f.

References cibst1(), d0, kcossn(), and rndc().

Referenced by cpi0decay().

!           special case for masseless 2 ptcl decay
!           such as pi0-->2g.
!     ************************************************
      implicit none
!----      include '../Zptcl.h'
#include  "Zptcl.h"
      type(ptcl):: p, p1, p2
      real*8 e1, e2, q1, cst, cs, sn, snt
!

      q1=p%mass/2
      e1=q1
      e2=e1
      call rndc(cst)
      cst=cst*2-1.d0
      call kcossn(cs, sn)
      snt=sqrt(1.d0-cst**2)
      p1%fm%p(1) = q1*snt*cs
      p1%fm%p(2) = q1*snt*sn
      p1%fm%p(4) = e1
      p1%fm%p(3) = q1*cst
!
      p2%fm%p(1) = -p1%fm%p(1)
      p2%fm%p(2) = -p1%fm%p(2)
      p2%fm%p(4) = e2
      p2%fm%p(3) = -p1%fm%p(3)
      call cibst1(1, p, p1, p1)
      call cibst1(2, p, p2, p2)

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c2bdcp()

subroutine c2bdcp	(	type(ptcl)	p,
		type(ptcl)	p1,
		real*8	cst,
		type(ptcl)	p2
	)

Definition at line 124 of file c2bdcy.f.

References cibst1(), d0, and kcossn().

Referenced by cg1pi0(), and cg1pic().

!      2body decay when the one particle decay angle is
!     fixed.
!     ************************************************ 
!      p: /ptcl/ input.  a particle which decays. 4momentum
!           must be given in a certain system K.  
!           The mass should be given too.
!      p1:  /ptcl/.input/outut. first particle. mass must be given.
!            as input.
!            as output, 4 momentum is given at K. Others unchaed
!      cst: real*8. input.  cos(of angle to the z axis)
!             of 1st ptcl at the rest system of p
!      p2:  /ptcl/ input/output. 2nd particle. same as 1st ptcl.
!
      implicit none
!----      include '../Zptcl.h'
#include  "Zptcl.h"
      type(ptcl):: p, p1, p2
      real*8 cst
!
      real*8 am, am1, am2, q1, e1, e2, cs, sn, snt
!
      am1 = p1%mass
      am2 = p2%mass
      am = p%mass
      q1=max(  (am**2- (am1+am2)**2)*(am**2-(am1-am2)**2), 0.d0)
      q1=sqrt( q1 )/am/2
      e1=sqrt(q1**2+am1**2)
      if(am1 .eq. am2) then
           e2=e1
      else
           e2=sqrt(q1**2+am2**2)
      endif
      call kcossn(cs, sn)
      snt=sqrt(1.d0-cst**2)
      p1%fm%p(1) = q1*snt*cs
      p1%fm%p(2) = q1*snt*sn
      p1%fm%p(3) = q1*cst
      p1%fm%p(4) = e1
!
      p2%fm%p(1) = -p1%fm%p(1)
      p2%fm%p(2) = -p1%fm%p(2)
      p2%fm%p(3) = -p1%fm%p(3)
      p2%fm%p(4) = e2
!         boost p1 into K
      call cibst1(1, p, p1, p1)

!        boost p2 into K
      call cibst1(2, p, p2, p2)

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c2bdcy()

subroutine c2bdcy	(	type(ptcl)	p,
		type(ptcl)	p1,
		type(ptcl)	p2
	)

Definition at line 44 of file c2bdcy.f.

References cibst1(), d0, kcossn(), and rndc().

Referenced by cbomegadcy(), cddbdc(), cddecay1(), cdeltadecay(), cdsdecay(), cetadecay(), cetapdecay(), cgzaidecay(), ck2pidecay(), ckmudecay(), ckpieneudecay(), clambdadcy(), cmuneudcy(), cnnbdc(), comgdc(), cphidc(), cpimudecay(), crhodc(), csigma0dcy(), csigmamdcy(), csigmapdcy(), and ctauneudcy().

!    ********************************************************
!        two body decay by pure phase space.  
!      Note that in case polarization exists,
!     this should not be used.
!     p: /ptcl/ Input.  particle which decays.
!               4 momentum and mass must be given
!               in a certain system K.
!    p1: /ptcl/ Input/Output. Decay product 1.
!               Mass must be given in input.
!               As output, 4 mementum is given in the
!               system K.  Other attributes are unchanged.
!    p2: /ptcl/ the same as above for 2nd ptcl.
! **** note:    for massless ptcl decay, use c2bdc0, which
!            is faster.
!
      implicit none
!----       include '../Zptcl.h'
#include  "Zptcl.h"
       type(ptcl):: p, p1, p2
       real*8 am, am1, am2, q1, e1, e2, cst, cs, sn, snt
!
        am = p%mass
        am1 = p1%mass
        am2 = p2%mass
        q1=max(  (am**2- (am1+am2)**2)*(am**2-(am1-am2)**2), 0.d0)
        q1=sqrt( q1 )/am/2
        e1=sqrt(q1**2+am1**2)
        if(am1 .eq. am2) then
           e2=e1
        else
           e2=sqrt(q1**2+am2**2)
        endif
        call rndc(cst)
        cst=cst*2-1.d0
        call kcossn(cs, sn)
        snt=sqrt(1.d0 - cst**2)
        p1%fm%p(1) = q1*snt*cs
        p1%fm%p(2) = q1*snt*sn
        p1%fm%p(4) = e1
        p1%fm%p(3) = q1*cst
        p2%fm%p(1) = -p1%fm%p(1)
        p2%fm%p(2) = -p1%fm%p(2)
        p2%fm%p(4) = e2
        p2%fm%p(3) = -p1%fm%p(3)
!         boost p1 into K
        call cibst1(1, p, p1, p1)

!          boost p2 into K
        call cibst1(2, p, p2, p2)

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