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