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2\section{Decay Table\label{DECAY}}
3
4 ISAJET uses an external table of decay modes. Particles can be
5put into the table in arbitrary order, but all modes for each particle
6must be grouped together. The table is rewound and read in before each
7run with a READ* format. Beginning with Version 7.41, the decay table
8must begin with a comment of the form
9\begin{verbatim}
10' ISAJET V7.41 11-JAN-1999 20:41:57'
11\end{verbatim}
12If this does not match the internal version number, a warning is
13printed. After this initial line, each entry must have the form
14\begin{verbatim}
15IDENT,MELEM,CBR,ID1,ID2,ID3,ID4,ID5/
16\end{verbatim}
17where IDENT is the code for the parent particle, MELEM specifies the
18decay matrix element, CBR is the cumulative branching ratio, and
19ID1,\dots,ID5 are the IDENT codes for the decay products. The
20currently defined values of MELEM are:
21\begin{center}
22\begin{tabular}{cl}
23\hline
24MELEM &\quad Matrix Element \\
25\hline
260 &\quad Phase Space \\
271 &\quad Dalitz decay \\
282 &\quad $\omega/\phi$ decay \\
293 &\quad $V-A$ decay \\
304 &\quad top decay: $V-A$ plus $W$ propagator \\
315 &\quad $\tau \to \ell \nu \bar \nu$ \\
326 &\quad $\tau \to \nu \pi$, $\nu K$ \\
337 &\quad $\tau \to \nu \rho$, $\nu a_1$ \\
34\hline
35\end{tabular}
36\end{center}
37The parent IDENT must be positive; the charge conjugate mode is used
38for the antiparticle. The values of CBR must of course be positive and
39monotonically increasing for each mode, with the last value being 1.00
40for each parent IDENT. The last parent IDENT code must be zero. Care
41should be taken in adding new modes, since there is no checking for
42validity. In some cases order is important; note in particular that
43quarks and gluons must always appear last so that they can be removed
44and fragmented into hadrons.
45
46 The format of the decay table for Versions 7.41 and later is
47incompatible with that for Versions 7.40 and earlier. Using an
48obsolete decay table will produce incorrect results.
49
50 The decay table is contained in patch ISADECAY.