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calc_kinem2_fixed.f
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calc_kinem2_fixed.f
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*CMZ : 30/05/2004 08.59.08 by H1 Saclay
*-- Author : Unknown 17/12/2003
****************************************************************
*
subroutine calc_kinem2_fixed(ibad,ioutkin,isca)
*
****************************************************************
IMPLICIT REAL*8(A-H,O-Z)
include 'dvcs.common'
include 'forpaw.common'
integer ibad,ioutkin
integer debug
common/debug/idebug
integer iprodsca
common /iprodsca/ iprodsca
real elepi,EGAMR,sweight,srad,elepin,ehadi
common /RADGEN/ elepi,EGAMR,sweight,srad,elepin,ehadi
common/dvcs_VAR/x_main,q_main,phi_main,t_main,ym_main
real rndm,pi_real,th_lo,en_lo,th_rg,en_rg,en_su,w_eg
real*8 mp
* 4-vectors : (px, py,pz; E)
* -> Lab frame :
dimension pli_l(4) ! incoming lepton in lab frame
dimension plo_l(4) ! outcoming lepton in lab frame
dimension pvgam_l(4) ! virtual photon in lab frame
dimension ppi_l(4) ! incoming proton in lab frame
dimension ppo_l(4) ! outcoming proton
dimension prgam_l(4) ! outcoming photon
* -> Proton rest frame :
dimension pli_tmp(4) ! incoming lepton in p-rest frame
dimension plo_tmp(4) ! outcoming lepton in p-rest frame
dimension pvgam_tmp(4) ! virtual photon in p-rest frame
dimension ppi_tmp(4) ! incoming proton in p-rest frame
dimension ppo_tmp(4) ! outcoming proton
dimension prgam_tmp(4) ! outcoming photon
dimension toto_li(4)
dimension toto_lo(4)
dimension toto_vgam(4)
* -> In p-rest frame, with z = - q_1^3
* (cf fig. 1 of Belitsky et al.)
dimension pli_b(4) ! incoming lepton
dimension plo_b(4) ! outcoming lepton
dimension pvgam_b(4) ! virtual photon
dimension ppi_b(4) ! incoming proton
dimension prgam_b(4) ! outcoming (real) photon
dimension ppo_b(4) ! outcoming proton
dimension beta(3),betar(3)
dimension ptmp(4)
dimension rot(3)
logical do_xaxis
common/xaxis/do_xaxis,i_xaxis
ibad = 0
ioutkin = 0
iprodsca = 0
mp = 0.93827d0
pi = datan(1.d0) * 4.0d0
elep = dble(elepi)
eproton = dble(stETARG)
shat = 2.0d0 * elep * mp + mp**2
cls print *,elep,eproton,sweight
q2 = qntp
xb = xntp
t = tntp
phi = phintp
cep dym = ym
dym = ym_main
y = q2/(xb*(shat - mp**2))
yntp = y
if (yntp.gt.stYMAX) then
ioutkin = 1
goto 999
endif
* -> incoming lepton in lab frame
pli_l(4) = elep
pli_l(3) = -elep
pli_l(1) = 0.d0
pli_l(2) = 0.d0
call v_copy(pli_l,plilab)
* -> radiated photon in lab frame
pvisr(1) = 0.
pvisr(2) = 0.
pvisr(3) = -real(egamr)
pvisr(4) = real(egamr)
* -> incoming proton in lab frame
ppi_l(4) = mp
ppi_l(3) = 0.0d0
ppi_l(1) = 0.0d0
ppi_l(2) = 0.0d0
call v_copy(ppi_l,ppilab)
* -> outcoming lepton in lab frame
plo_l(4) = elep*(1.-y) + q2 / (4.*elep)
thetal = dacos(1. - 2.*elep*(1.-y)/plo_l(4) )
ccc print *,thetal*180/3.14,'thetal'
phil = dble(rndm(0.)) *2.d0 * pi
plo_l(1) = plo_l(4) * dsin(thetal) * dcos(phil)
plo_l(2) = plo_l(4) * dsin(thetal) * dsin(phil)
plo_l(3) = plo_l(4) * dcos(thetal)
call v_copy(plo_l,plolab)
* --------------------------------------
ccc if (plo_l(4).lt.stELMIN) then
ccc ioutkin = 1
ccc goto 999
ccc endif
* --------------------------------------
* -> virtual photon in lab frame
do i=1,4
pvgam_l(i) = pli_l(i) - plo_l(i)
enddo
call v_copy(pvgam_l,pvglab)
if (idebug.eq.1) then
write(6,*) ' '
write(6,*) 'START'
write(6,*) ' '
write(6,*) ' ------ In lab frame :'
write(6,*) 'Incoming lepton :'
call v_print(pli_l)
print *,elepi,abs(stELEP)
write(6,*) 'Incoming proton : '
call v_print(ppi_l)
print *,eproton,stETARG
write(6,*) 'Outcoming lepton : '
call v_print(plo_l)
print *,y,q2,elep*(1.-y) + q2 / (4.*elep),
+ 1. - 2.*elep*(1.-y)/plo_l(4)
write(6,*) 'Virtual photon : '
call v_print(pvgam_l)
endif
* --- Boost to p-rest frame, same system axis ---
call v_copy8(pli_l,pli_tmp)
call v_copy(pli_tmp,pliprf)
call v_copy8(plo_l,plo_tmp)
call v_copy(plo_tmp,ploprf)
call v_copy8(ppi_l,ppi_tmp)
call v_copy(ppi_tmp,ppiprf)
call v_copy8(pvgam_l,pvgam_tmp)
call v_copy(pvgam_tmp,pvgprf)
if (idebug.eq.1) then
write(6,*) ' '
write(6,*) '----- In p-rest frame : '
write(6,*) 'incoming lepton :'
call v_print(pli_tmp)
write(6,*) 'incoming proton :'
call v_print(ppi_tmp)
write(6,*) 'outcoming lepton :'
call v_print(plo_tmp)
write(6,*) 'virtual photon :'
call v_print(pvgam_tmp)
endif
* --- Rotate the system axis, z = -q_1^3 ---
do i=1,3
rot(i) = -pvgam_tmp(i)
enddo
do_xaxis = .true.
i_xaxis = 1
call rotate(pli_tmp,rot,1,pli_b)
do_xaxis = .false.
call v_copy(pli_b,plibel)
call rotate(plo_tmp,rot,1,plo_b)
call rotate(pvgam_tmp,rot,1,pvgam_b)
ccc call rotate(ppi_tmp,rot,1,ppi_b)
call v_copy8(ppi_b,ppi_tmp)
call v_copy(plo_b,plobel)
call v_copy(pvgam_b,pvgbel)
call v_copy(ppi_b,ppibel)
if (idebug.eq.1) then
write(6,*) ' '
write(6,*) '----- in Belitsky frame : '
write(6,*) 'incoming lepton :'
call v_print(pli_b)
write(6,*) 'incoming proton :'
call v_print(ppi_b)
write(6,*) 'outcoming lepton :'
call v_print(plo_b)
write(6,*) 'virtual photon :'
call v_print(pvgam_b)
endif
* -> Outcoming proton, in Belitsky frame :
if (stIELAS.eq.1) then
ppo_b(4) = mp - t / (2.0d0 * mp)
qpo_b = dsqrt( t*(t-4*mp**2) ) / (2.d0*mp)
p2 = qpo_b
q13 = - (q2 / (2.*mp*xb))*dsqrt(1.+4.*mp**2*xb**2/q2)
q20 = (t + q2/xb ) / (2.*mp)
else
ppo_b(4) = (dym**2+mp**2) / (2.*mp)
ppo_b(4) = ppo_b(4) - t / (2.0d0 * mp)
qpo_b = dsqrt(ppo_b(4)**2 -dym**2)
p2 = qpo_b
q13 = - (q2 / (2.*mp*xb))*dsqrt(1.+4.*mp**2*xb**2/q2)
q20 = (t + q2/xb -(dym**2-mp**2) ) / (2.*mp)
endif
ccc = q13**2-q20**2+p2**2
ccc = ccc / (2. * p2 * q13)
cost = ccc
if ( (cost.gt.1).or.(cost.lt.-1.) ) then
write(6,*) 'pb cost ',cost,dym,xb,q2,t,phi
ibad = 1
ioutkin = 1
goto 999
endif
thetan = dacos(cost)
CLS>> NEW
phi_p = dble(atan2(plobel(2),plobel(1))) -
+ dble(rndm(0.)) *2.d0 * pi
CLS =========================================
ppo_b(1) = qpo_b * dcos(phi_p) * dsin(thetan)
ppo_b(2) = qpo_b * dsin(phi_p) * dsin(thetan)
ppo_b(3) = qpo_b * dcos(thetan)
call v_copy(ppo_b,ppobel)
if (idebug.eq.1) then
write(6,*) 'Outcoming proton :'
call v_print(ppo_b)
call v_print4(ppobel)
endif
* -> Outcoming (real) photon, in Belitsky frame :
do i=1,4
prgam_b(i) = pli_b(i) + ppi_b(i) - plo_b(i) - ppo_b(i)
enddo
call v_copy(prgam_b,prgbel)
* --- Rotate back the system axis
call rotate(ppo_b,rot,-1,ppo_tmp)
call v_copy(ppo_tmp,ppoprf)
call rotate(prgam_b,rot,-1,prgam_tmp)
call v_copy(prgam_tmp,prgprf)
if (idebug.eq.1) then
write(6,*) ' '
write(6,*) '----- Back to standard axis system (checks) '
call rotate(pvgam_b,rot,-1,toto_vgam)
write(6,*) 'virt gamma back to standard axis (check) '
call v_print(toto_vgam)
call rotate(pli_b,rot,-1,toto_li)
write(6,*) 'incoming lepton back to st axis (check) '
call v_print(toto_li)
call rotate(plo_b,rot,-1,toto_lo)
write(6,*) 'outcoming lepton back to st axis (check) '
call v_print(toto_lo)
write(6,*) 'Outcoming proton :'
call v_print4(ppoprf)
write(6,*) 'Real photon :'
call v_print4(prgprf)
endif
* --- Boost back from p-rest frame to lab frame
call v_copy8(ppo_tmp,ppo_l)
call v_copy8(prgam_tmp,prgam_l)
call v_copy(ppo_l,ppolab)
call v_copy(prgam_l,prglab)
if (idebug.eq.1) then
call check(plilab,ppilab,plolab,ppolab,prglab)
call check(pliprf,ppiprf,ploprf,ppoprf,prgprf)
call check(plibel,ppibel,plobel,ppobel,prgbel)
write(6,*) ' '
write(6,*) 'END'
endif
pi_real = atan(1.0) * 4.0
th_lo = atan2(sqrt(plolab(1)**2+plolab(2)**2),plolab(3))
th_lo = th_lo*180./pi_real
en_lo = plolab(4)
th_rg = atan2(sqrt(prglab(1)**2+prglab(2)**2),prglab(3))
th_rg = th_rg*180./pi_real
en_rg = prglab(4)
ccc print *,th_lo,en_lo,th_rg,en_rg
en_su = en_lo+en_rg
w_eg = (plolab(4)+prglab(4))**2
w_eg = w_eg-(plolab(1)+prglab(1))**2
w_eg = w_eg-(plolab(2)+prglab(2))**2
w_eg = w_eg-(plolab(3)+prglab(3))**2
w_eg = sqrt(w_eg)
if (idebug.eq.1) then
print *,'M(eg) invariant mass = ',w_eg
endif
if (th_lo.lt.stTHLMIN) ioutkin = 1
if (th_lo.gt.stTHLMAX) ioutkin = 1
cls if (en_lo.lt.stELMIN) ioutkin = 1
if (th_rg.lt.stTHGMIN) ioutkin = 1
if (th_rg.gt.stTHGMAX) ioutkin = 1
cls if (en_rg.lt.stEGMIN) ioutkin = 1
CLS>> NEW
if (en_su.lt.stELMIN) ioutkin = 1 ! v3 => see README file...
if (w_eg.lt.stM12MIN) ioutkin = 1
if (en_lo.lt.stELMB) ioutkin = 1
if (en_rg.lt.stEGMB) ioutkin = 1
if (stIRAD.eq.1) then
if (EGAMR.lt.stEIMIN) ioutkin = 1
endif
isca = iprodsca
ccc print *,'th_lo=',th_lo,'ioutkin=',ioutkin
999 continue
return
end