HIJING/hijing1_36/attrad.F

   1 * $Id$
   2
   3 C
   4 C
   5 C
   6 C****************************************************************
   7 C       conduct soft radiation according to dipole approxiamtion
   8 C****************************************************************
   9         SUBROUTINE ATTRAD(IERROR)
  10 C
  11 #include "hiparnt.inc"
  12 #include "hijdat.inc"
  13 #include "lujets_hijing.inc"
  14         SAVE
  15         IERROR=0
  16
  17 C.....S INVARIANT MASS-SQUARED BETWEEN PARTONS I AND I+1......
  18 C.....SM IS THE LARGEST MASS-SQUARED....
  19
  20 40      SM=0.
  21         DO 30 I=1,N-1
  22            S=2.*(P(I,4)*P(I+1,4)-P(I,1)*P(I+1,1)-P(I,2)*P(I+1,2)
  23      &          -P(I,3)*P(I+1,3))+P(I,5)**2+P(I+1,5)**2
  24            IF(S.LT.0.) S=0.
  25            WP=SQRT(S)-1.5*(P(I,5)+P(I+1,5))
  26            IF(WP.GT.SM) THEN
  27               PBT1=P(I,1)+P(I+1,1)
  28               PBT2=P(I,2)+P(I+1,2)
  29               PBT3=P(I,3)+P(I+1,3)
  30               PBT4=P(I,4)+P(I+1,4)
  31               BTT=(PBT1**2+PBT2**2+PBT3**2)/PBT4**2
  32               IF(BTT.GE.1.0-1.0E-10) GO TO 30
  33               IF((I.NE.1.OR.I.NE.N-1).AND.
  34      &             (K(I,2).NE.21.AND.K(I+1,2).NE.21)) GO TO 30
  35               JL=I
  36               SM=WP
  37            ENDIF
  38 30      CONTINUE
  39         S=(SM+1.5*(P(JL,5)+P(JL+1,5)))**2
  40         IF(SM.LT.HIPR1(5)) GOTO 2
  41
  42 C.....MAKE PLACE FOR ONE GLUON.....
  43         IF(JL+1.EQ.N) GOTO 190
  44         DO 160 J=N,JL+2,-1
  45                 K(J+1,1)=K(J,1)
  46                 K(J+1,2)=K(J,2)
  47                 DO 150 M=1,5
  48 150                     P(J+1,M)=P(J,M)
  49 160             CONTINUE
  50 190     N=N+1
  51
  52 C.....BOOST TO REST SYSTEM FOR PARTICLES JL AND JL+1.....
  53         P1=P(JL,1)+P(JL+1,1)
  54         P2=P(JL,2)+P(JL+1,2)
  55         P3=P(JL,3)+P(JL+1,3)
  56         P4=P(JL,4)+P(JL+1,4)
  57         BEX=-P1/P4
  58         BEY=-P2/P4
  59         BEZ=-P3/P4
  60         IMIN=JL
  61         IMAX=JL+1
  62         CALL ATROBO(0.,0.,BEX,BEY,BEZ,IMIN,IMAX,IERROR)
  63         IF(IERROR.NE.0) RETURN
  64 C.....ROTATE TO Z-AXIS....
  65         PABS=(P(JL,4)-P(JL,5))*(P(JL,4)+P(JL,5))
  66         IF (PABS .GT. 0) THEN
  67           CTH=P(JL,3)/SQRT(PABS)
  68         ELSE
  69           CTH=SIGN(1.,P(JL,3))
  70         ENDIF
  71         IF(ABS(CTH).GT.1.0)  CTH=MAX(-1.,MIN(1.,CTH))
  72         THETA=ACOS(CTH)
  73         PHI=ULANGL_HIJING(P(JL,1),P(JL,2))
  74         CALL ATROBO(0.,-PHI,0.,0.,0.,IMIN,IMAX,IERROR)
  75         CALL ATROBO(-THETA,0.,0.,0.,0.,IMIN,IMAX,IERROR)
  76
  77 C.....CREATE ONE GLUON AND ORIENTATE.....
  78
  79 1       CALL AR3JET(S,X1,X3,JL)
  80         CALL ARORIE(S,X1,X3,JL)
  81         IF(HIDAT(2).GT.0.0) THEN
  82            PTG1=SQRT(P(JL,1)**2+P(JL,2)**2)
  83            PTG2=SQRT(P(JL+1,1)**2+P(JL+1,2)**2)
  84            PTG3=SQRT(P(JL+2,1)**2+P(JL+2,2)**2)
  85            PTG=MAX(PTG1,PTG2,PTG3)
  86            IF(PTG.GT.HIDAT(2)) THEN
  87               FMFACT=EXP(-(PTG**2-HIDAT(2)**2)/HIPR1(2)**2)
  88               IF(RLU_HIJING(0).GT.FMFACT) GO TO 1
  89            ENDIF
  90         ENDIF
  91 C.....ROTATE AND BOOST BACK.....
  92         IMIN=JL
  93         IMAX=JL+2
  94         CALL ATROBO(THETA,PHI,-BEX,-BEY,-BEZ,IMIN,IMAX,IERROR)
  95         IF(IERROR.NE.0) RETURN
  96 C.....ENUMERATE THE GLUONS.....
  97         K(JL+2,1)=K(JL+1,1)
  98         K(JL+2,2)=K(JL+1,2)
  99         K(JL+2,3)=K(JL+1,3)
 100         K(JL+2,4)=K(JL+1,4)
 101         K(JL+2,5)=K(JL+1,5)
 102         P(JL+2,5)=P(JL+1,5)
 103         K(JL+1,1)=2
 104         K(JL+1,2)=21
 105         K(JL+1,3)=0
 106         K(JL+1,4)=0
 107         K(JL+1,5)=0
 108         P(JL+1,5)=0.
 109 C----THETA FUNCTION DAMPING OF THE EMITTED GLUONS. FOR HADRON-HADRON.
 110 C----R0=VFR(2)
 111 C       IF(VFR(2).GT.0.) THEN
 112 C       PTG=SQRT(P(JL+1,1)**2+P(JL+1,2)**2)
 113 C       PTGMAX=WSTRI/2.
 114 C       DOPT=SQRT((4.*PAR(71)*VFR(2))/WSTRI)
 115 C       PTOPT=(DOPT*WSTRI)/(2.*VFR(2))
 116 C       IF(PTG.GT.PTOPT) IORDER=IORDER-1
 117 C       IF(PTG.GT.PTOPT) GOTO 1
 118 C       ENDIF
 119 C-----
 120         IF(SM.GE.HIPR1(5)) GOTO 40
 121
 122 2       K(1,1)=2
 123         K(1,3)=0
 124         K(1,4)=0
 125         K(1,5)=0
 126         K(N,1)=1
 127         K(N,3)=0
 128         K(N,4)=0
 129         K(N,5)=0
 130
 131         RETURN
 132         END