CDECK  ID>, HWSGQQ.

*CMZ :-        -26/04/91  11.11.56  by  Bryan Webber

*-- Author :    Bryan Webber

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

      FUNCTION HWSGQQ(QSCA)

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

C     CORRECTION TO GLUON STRUCTURE FUNCTION FOR BACKWARD EVOLUTION:

C     G->Q-QBAR PART OF FORM FACTOR

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

      INCLUDE 'HERWIG61.INC'

      DOUBLE PRECISION HWSGQQ,HWUALF,QSCA,GG

      EXTERNAL HWUALF

      GG=HWUALF(1,QSCA)**(-ONE/BETAF)

      IF (GG.LT.ONE) GG=ONE

      IF (QSCA.GT.RMASS(6)) THEN

        HWSGQQ=GG**6

      ELSEIF (QSCA.GT.RMASS(5)) THEN

        HWSGQQ=GG**5

      ELSEIF (QSCA.GT.RMASS(4)) THEN

        HWSGQQ=GG**4

      ELSE

        HWSGQQ=GG**3

      ENDIF

      END