For details, see comment lines in the respective fortran files.
( http://xxx.lanl.gov/abs/hep-ph/9903282 , 163 kb) to be published in Eur. Phys. J. C 1999.
These PDF's use quadratic interpolation of attached tables. A parametrized version of the same PDF's without external tables is under construction. They will become available later.
This package contains 7 sets of CTEQ5 PDF's; plus two updated ones. The undated CTEQ5M1 and CTEQHQ1 use an improved evolution code. Both the original and the updated ones fit current data with comparable accuracy. The CTEQHQ1 set also involve a different choice of scale, hence differs from CTEQHQ slightly more. It is preferred over CTEQ5HQ. Details are: --------------------------------------------------------------------------- Iset PDF Description Alpha_s(Mz) Lam4 Lam5 Table_File --------------------------------------------------------------------------- 1 CTEQ5M Standard MSbar scheme 0.118 326 226 cteq5m.tbl 2 CTEQ5D Standard DIS scheme 0.118 326 226 cteq5d.tbl 3 CTEQ5L Leading Order 0.127 192 146 cteq5l.tbl 4 CTEQ5HJ Large-x gluon enhanced 0.118 326 226 cteq5hj.tbl 5 CTEQ5HQ Heavy Quark 0.118 326 226 cteq5hq.tbl 6 CTEQ5F3 Nf=3 FixedFlavorNumber 0.106 (Lam3=395) cteq5f3.tbl 7 CTEQ5F4 Nf=4 FixedFlavorNumber 0.112 309 XXX cteq5f4.tbl -------------------------------------------------------- 8 CTEQ5M1 Improved CTEQ5M 0.118 326 226 cteq5m1.tbl 9 CTEQ5HQ1 Improved CTEQ5HQ 0.118 326 226 ctq5hq1.tbl --------------------------------------------------------------------------- The available applied range is 10^-5 < x < 1 and 1.0 < Q < 10,000 (GeV). Lam5 (Lam4, Lam3) represents Lambda value (in MeV) for 5 (4,3) flavors. The matching alpha_s between 4 and 5 flavors takes place at Q=4.5 GeV, which is defined as the bottom quark mass, whenever it can be applied. The Table_Files are assumed to be in the working directory. Before using the PDF, it is necessary to do the initialization by Call SetCtq5(Iset) where Iset is the desired PDF specified in the above table. The function Ctq5Pdf (Iparton, X, Q) returns the parton distribution inside the proton for parton [Iparton] at [X] Bjorken_X and scale [Q] (GeV) in PDF set [Iset]. Iparton is the parton label (5, 4, 3, 2, 1, 0, -1, ......, -5) for (b, c, s, d, u, g, u_bar, ..., b_bar), whereas CTEQ5F3 has, by definition, only 3 flavors and gluon; CTEQ5F4 has only 4 flavors and gluon.For detailed information on the parameters used, e.q. quark masses, QCD Lambda, ... etc., see info lines at the beginning of the Table_Files.
These programs, as provided, are in double precision. By removing the "Implicit Double Precision" lines, they can also be run in single precision.
If you have detailed questions concerning these CTEQ5 distributions, or if you find problems/bugs using this package, direct inquires to Hung-Liang Lai (lai@phys.nthu.edu.tw) or Wu-Ki Tung (Tung@pa.msu.edu).