CTEQ Parton distributions

The CTEQ parton distributions are produced by the various subsets of the CTEQ group. The authors for the CTEQ3 distribution, for instance, are H.L. Lai, J. Botts, J. Huston, J.G. Morfin, J.F. Owens, J. Qiu, W.K. Tung and H. Weerts.

Name convention for CTEQ distributions

CTEQnS where

n : version number
S : Normally a factorization scheme label: = [M L D] for [MS-bar, Lowest Order, DIS] respectively.
Sometimes S denotes some special characteristic of the set.

Thus for example, CTEQ4M gives the fourth set of CTEQ parton distributions in the MSbar scheme, while CTEQ4HJ is a special fit that emphasizes high ET jet data.

References

CTEQ Source code

Smoothing

For the CTEQ4 partons, we have made a parton table using the table interpolation supplied by CTEQ. However, our table interpolation requires that the parton distributions represented in the tables be smooth functions of x and Q2. At some places (where the values of the parton distributions are small) the functions given by the CTEQ parton tables are not smooth. We have, therefore, applied a smoothing operation to the table in our format. Here is a picture illustrating our smoothed version and the original CTEQ version. For previous CTEQ parton distributions, we did not find a need for smoothing.

FORTRAN code for creating these tables

Parton distribution tables


Davison E. Soper and Parvez Anandam
Institute of Theoretical Science, University of Oregon, Eugene OR 97403 USA
soper@bovine.uoregon.edu
email: anandam@darkwing.uoregon.edu