MRST2001: partons and alpha_S from precise deep inelastic scattering and Tevatron jet data

Abstract

We use all the available new precise data for deep inelastic and related hard scattering processes to perform NLO global parton analyses. These new data allow an improved determination of partons and, in particular, the inclusion of the recent measurements of the structure functions at HERA and of the inclusive jets at the Tevatron help to determine the gluon distribution and alpha_S better than ever before. We find a somewhat smaller gluon at low x than previous determinations and that alpha_S(M_Z^2) = 0.119 +/- 0.002 (expt.) +/- 0.003 (theory).

Revised version to be published in Eur. Phys. J.. Various modifications, including new appendix detailing effect of correlated errors for HERA data. Parton sets unchanged. 35 pages, 16 figures. FORTRAN code for parton sets can be found at http://durpdg.dur.ac.uk/hepdata/mrs