First commit.

[u/mrichter/AliRoot.git] / ISAJET / isasusy / ssgwt4.F

diff --git a/ISAJET/isasusy/ssgwt4.F b/ISAJET/isasusy/ssgwt4.F
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+++ b/ISAJET/isasusy/ssgwt4.F
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+#include "isajet/pilot.h"
+        REAL FUNCTION SSGWT4(E)
+C-----------------------------------------------------------------------
+C          SSGLBF: glss -> wiss + tp + bb
+C          Baer's FTBW12; EQ. A.3D OF BTW, MODIFIED FOR MB=/0
+C          Drees' G_4
+C-----------------------------------------------------------------------
+#if defined(CERNLIB_IMPNONE)
+      IMPLICIT NONE
+#endif
+#include "isajet/sssm.inc"
+#include "isajet/sspar.inc"
+#include "isajet/sstmp.inc"
+        REAL E
+        DOUBLE PRECISION ET,MWI,MG,MT,MSB,MST,PT,EBMX
+        DOUBLE PRECISION BOT,TOP,DFTBW,EBMN,XX
+        DOUBLE PRECISION MB,Z,RDL,DEN,R1,R2,R3,SSDLAM,SN
+C
+        ET=E
+        MWI=TMP(1)
+        MG=TMP(2)
+        MT=TMP(3)
+        MSB=TMP(4)
+        MST=TMP(6)
+        SN=TMP(8)
+        MB=AMBT
+C
+C            Rewrite PT=DSQRT(ET**2-MT**2)
+        PT=DSQRT((ET-MT)*(ET+MT))
+        Z=(MG**2+MT**2-2*MG*ET+MB**2-MWI**2)/2.
+        R1=1.D0+MT**2/MG**2-2.D0*ET/MG
+        R2=MB**2/MG**2
+        R3=MWI**2/MG**2
+        RDL=DSQRT(DMAX1(0.D0,SSDLAM(R1,R2,R3)))
+        DEN=MG**2+MT**2-2*ET*MG
+        EBMX=(2*Z*(1.D0-ET/MG)+PT*MG*RDL)*MG/2.D0/DEN
+        EBMN=(2*Z*(1.D0-ET/MG)-PT*MG*RDL)*MG/2.D0/DEN
+        XX=(MSB**2+2*MG*EBMX-MG**2)/(MSB**2+2*MG*EBMN-MG**2)
+        TOP=EBMX-EBMN-(MSB**2-2*MG*ET+MT**2-MWI**2)*DLOG(XX)/2.D0/MG
+        BOT=(MG**2+MT**2-2*MG*ET-MST**2)
+        DFTBW=-SN*MG*MWI*TOP/BOT
+        SSGWT4=DFTBW
+        RETURN
+        END