pyrvg2.f

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C*********************************************************************
 
C...PYRVG2
C...Integrand for L-R interference contributions
 
      FUNCTION pyrvg2(X)
 
      IMPLICIT NONE
      common/pyrvpm/rm(0:3),a(2),b(2),resm(2),resw(2),mflag
      DOUBLE PRECISION x, rm, a, b, resm, resw, deltay, pyrvs
      DOUBLE PRECISION rvs,pyrvg2,e2,e3,c1,sr1,sr2
      LOGICAL mflag
      SAVE/pyrvpm/
      c1     = 2d0*sqrt(max(0d0,x))
      rvs    = pyrvs(x,x,resm(1),resw(1),resm(2),resw(2))
      IF (.NOT.mflag) THEN
        e2     = x/c1
        e3     = (rm(0)**2-x)/c1
        deltay = 4d0*e2*e3
        pyrvg2 = deltay*rvs*x*(a(1)*a(2)+b(1)*b(2))*(rm(0)**2-x)
      ELSE
        e2     = (x-rm(1)**2+rm(2)**2)/c1
        e3     = (rm(0)**2-x-rm(3)**2)/c1
        sr1    = sqrt(max(0d0,e2**2-rm(2)**2))
        sr2    = sqrt(max(0d0,e3**2-rm(3)**2))
        deltay = 4d0*sr1*sr2
        pyrvg2 = deltay*rvs*(x-rm(1)**2-rm(2)**2)*((a(1)*a(2)
     &       + b(1)*b(2))*(rm(0)**2+rm(3)**2-x)
     &       + 2d0*(a(1)*b(2)+a(2)*b(1))*rm(3)*rm(0))
      ENDIF
      RETURN
      END