Note for authors of hzxxxxx routines

In order to work with this library, hzxxxxx routines have to fulfill some additional requirements.

• Add the common block HZNLO to your routine.
• Initialize the variable NLO to 0 in the iflag.eq.1 section.
• Add an if clause to every hbook fill or weight summation line in order to check, whether the current event counts for the desired process, e.g. check for total cross sections, whether the process is a $\cal {O}$(1) born term or a $\cal {O}$($\alpha_{s}^{}$) correction. This check can easily be done using the variables defined in the HZNLO common block.

The HZNLO common block is defined as follows:

      INTEGER NLO, TOT, DIJET, TRIPJET, QUADJET
      COMMON /HZNLO/NLO, TOT, DIJET, TRIPJET, QUADJET

An example might look like:

      IF (iflag.eq.1) THEN
C... init step
        NLO=0
      ELSE IF (iflag.eq.2) THEN
C... fill step

C... make some phase space cuts

CTH add total x-section
        IF ((NLO.eq.1).AND.(TOT.ne.1)) GOTO 11112
         nall=nall+xw
11112   CONTINUE

C... run some jet algorithm and make some cuts on dijet events

        IF (twojet) THEN
          IF ((NLO.eq.1).AND.(DIJET.ne.1)) GOTO 11114
            nall2=nall2+xw
            call hfill(121,x,0.,xw)
            call hfill(131,q2,0.,xw)
11114     CONTINUE
        ENDIF
      ENDIF