fjetrig.f

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C
C
C
  FUNCTION fjetrig(X,WGT)
  IMPLICIT REAL*8(a-h,o-z)
  REAL hipr1(100),hint1(100),ptmax,ptmin
        common/hiparnt/hipr1,ihpr2(50),hint1,ihnt2(50)
        SAVE  /hiparnt/
  dimension x(10)
  ptmin=abs(hipr1(10))-0.25
  ptmin=max(ptmin,hipr1(8))
  am2=0.d0
  IF(ihpr2(3).EQ.3) THEN
     am2=hipr1(7)**2
     ptmin=max(0.0,hipr1(10))
  ENDIF
  ptmax=abs(hipr1(10))+0.25
  IF(hipr1(10).LE.0.0) ptmax=hint1(1)/2.0-am2
  IF(ptmax.LE.ptmin) ptmax=ptmin+0.25
  pt2=(ptmax**2-ptmin**2)*x(1)+ptmin**2
  amt2=pt2+am2
  xt=2.0*dsqrt(amt2)/hint1(1)
  ymx1=dlog(1.0/xt+dsqrt(1.0/xt**2-1.0))
  y1=2.0*ymx1*x(2)-ymx1
  ymx2=dlog(2.0/xt-dexp(y1))
  ymn2=dlog(2.0/xt-dexp(-y1))
  y2=(ymx2+ymn2)*x(3)-ymn2
  IF(ihpr2(3).EQ.3) THEN
     gtrig=2.0*ghvq(y1,y2,amt2)
  ELSE IF(ihpr2(3).EQ.2) THEN
     gtrig=2.0*gphoton(y1,y2,pt2)
  ELSE
     gtrig=g(y1,y2,pt2)
  ENDIF
  fjetrig=2.0*ymx1*(ymx2+ymn2)*(ptmax**2-ptmin**2)
     &    *gtrig/2.0
  RETURN
  END