Документ взят из кэша поисковой машины. Адрес оригинального документа : http://theory.sinp.msu.ru/comphep_html/tutorial/node35.html
Дата изменения: Wed Aug 9 20:40:47 2000
Дата индексирования: Mon Oct 1 22:42:50 2012
Кодировка:

Cuts

The Cuts menu function opens a table for cuts definition. This table consists of three columns. The phase space function in notations of Section must be written in the first column. The second and the third columns define the minimal and maximal limits for this function. If one of them is empty the corresponding limit is not applied.

Input formats for limits are different for the Fortran  and C  realizations. In the case of n_comphep_c and interpreter sessions the user may type in the corresponding fields any algebraic formula which contains numbers and identifiers enumerated in the Model parameters menu. Parentheses "()" and operations $''+,-,/,*,**,sqrt()''$ also are permitted.

In the case of n_comphep_f session only numbers are expected in the corresponding columns. To escape an input in $GeV^2$ units in the case of squared momenta function

$V_{min} < S(momenta~set) < V_{max}$,

the n_comphep_f program asks the user to put $V_{min}/\sqrt{\vert V_{min}\vert}$ and $V_{max}/\sqrt{\vert V_{max}\vert}$ in the relevant cells.

It is very important to note that only the cuts on masses and squared momenta (the S and M cases) are realized via a reduction of the phase space. Other ones are realized by multiplication of squared matrix element by a step function.