CDECK  ID>, HWDRM4.

*CMZ :-        -20/07/99  10:56:12  by  Peter Richardson

*-- Author :    Peter Richardson

C-----------------------------------------------------------------------

      FUNCTION HWDRM4(X,Y,MA,MB,MC,MD,MR1,MR2,GAM1,GAM2,A1,A2,B1,B2)

C-----------------------------------------------------------------------

C     Function to compute the interference part of a 3-body

C     R-parity decay

C-----------------------------------------------------------------------

      IMPLICIT NONE

      DOUBLE PRECISION X,Y,MA,MB,MC,MD,A1,A2,B1,B2,HWDRM4,MR1,MR2,GAM1

     &                 ,GAM2

C

      HWDRM4  = 2*((GAM1*GAM2*MR1*MR2 + (X - MR1**2)*(Y - MR2**2))*

     &    (A2*B1*MC*MD*(X - MA**2 - MB**2) +

     &      A1*A2*MA*MC*(X + Y - MA**2 - MC**2) +

     &      A1*B2*MA*MD*(Y - MB**2 - MC**2) +

     &      B1*B2*(X*Y - MA**2*MC**2 - MB**2*MD**2)))/

     &  (((X-MR1**2)**2+GAM1**2*MR1**2)*((Y-MR2**2)**2+GAM2**2*MR2**2))

      END