Документ взят из кэша поисковой машины. Адрес оригинального документа : http://theory.sinp.msu.ru/comphep_html/tutorial/node84.html
Дата изменения: Tue Aug 15 14:34:46 2000
Дата индексирования: Mon Oct 1 22:39:15 2012
Кодировка:
CTEQ4m  distribution functions MRS structure functions Distribution functions and beam spectra Distribution functions and beam spectra Contents

CTEQ4m  distribution functions

There are several sets of disribution functions presented by CTEQ collaboration which describe the densities of quarks and gluons in (anti)proton. In CompHEP  we have implemented the CTEQ4m[CTEQ-1997] set. Apart from the Feynman variable $x$ they depends on the QCD-scale parameter $Q$. The available range is

\begin{displaymath} \begin{array}{lcl} 10^{-5} & < x < & 1; \\ 1.6 & < Q < & 10000 \; \mbox{GeV}. \end{array} \end{displaymath}

For points outside these ranges the extrapolation is used and the corresponding warning is directed to the standard output file.

The CTEQ4m  set of functions is produced in the framework of the next-to-leading calculations in the standard $\overline{MS}$ scheme with $\alpha_s(M_Z) = 0.116$. See further explanations in [CTEQ-1997].