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subroutine hstlxx(s1,t2,gc,smass,swidth , hst)
c- by RF - Mar. 2006
c
c This subroutine computes an off-shell scalar current from the three-
c scalar coupling.
c
c input:
c complex s1(3) : first scalar s1
c complex t2(3) : internal particle (scalar) s2
c complex gc : coupling constant ghhh
c real smass : mass of OUTPUT scalar s'
c real swidth : width of OUTPUT scalar s'
c
c output:
c complex hst(3) : scalar current j(s':s1,s2)
c
implicit none
INTEGER DIM
PARAMETER(DIM=18)
double complex s1(DIM),t2(DIM),hst(DIM),dg
double precision q(0:3),smass,swidth,q2,gc
hst(2) = s1(2)+t2(2)
hst(3) = s1(3)+t2(3)
q(0) = -dble( hst(2))
q(1) = -dble( hst(3))
q(2) = -dimag(hst(3))
q(3) = -dimag(hst(2))
q2 = q(0)**2-(q(1)**2+q(2)**2+q(3)**2)
dg = gc /dcmplx( q2-smass**2, smass*swidth )
hst(1) = dg*s1(1)*t2(1)
return
end
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