SUBROUTINE QIPLST - Set up masses of outgoing partons

In this routine to each outgoing parton, set up in QIGLST and QIGPAR, an appropriate mass (default HERWIG [1] mass for quarks/anti-quarks, default gluon mass from QIINIT) is set up. This is done consecutively:

• The routine starts with the first column (``string'') in the array of parton identification labels, QIPTYP(JLP,ILP), (ILP=1) and looks in this column for the first entry from above which is marked as outgoing. The mass to the first outgoing parton, QIPHEP(5,1), is set up.
• One moves further down in the first column and looks for the next entry which is marked as outgoing and associates with it the mass of the second outgoing parton, QIPHEP(5,2), etc. until there are no more partons in the first column.
• One moves to the next column and repeats the procedure above.

Table 1: Variables set in QIPLST.

Name	Description
QIPHEP(5,IHEP)	Mass of the IHEP'th outgoing parton from instanton subprocess
QINHEP	Number of outgoing partons from instanton subprocess, $2\,n_f-1 + n_g$

Let us illustrate this on the example given in the description of the subroutine QIGLST: Suppose we have $n_f=3,n_g=3$, and that $q^\prime$ is a quark with with particle data group identity 3. Then the parton type array QIPTYP(JLP,ILP) might be of the form

$$\begin{array}{cc\vert cccccc} & & \multicolumn{6}{\vert c}{... ...NLIS(ILP)} & & 3 & 4 & 3 & 0 & \ldots & 0 \\ \end{array}\, .$$ (1)

The bold-face gluon entry $\bf 21$ and the bold-face antiquark entry $\bf -3$ are to indicate that these partons are marked as incoming. The outcome of the procedure described above is shown in Table 2.

Table 2: Example of mass assignments.

QIPHEP(5,1)	Mass of quark 1
QIPHEP(5,2)	Mass of antiquark -2
QIPHEP(5,3)	Mass of quark 2
QIPHEP(5,4)	Mass of gluon
QIPHEP(5,5)	Mass of gluon
QIPHEP(5,6)	Mass of quark 3
QIPHEP(5,7)	Mass of gluon
QIPHEP(5,8)	Mass of antiquark -1