Improved Parton Distributions from Global Analysis of Recent Deep Inelastic Scattering and Inclusive Jet Data

The impact of recent precision measurements of DIS structure functions and inclusive jet production at the Tevatron on the global QCD analysis of parton distribution functions is studied in detail. Particular emphasis is placed on exploring the range of variation of the gluon distribution $G(x,Q)$ allowed by these new data. The strong coupling of $G(x,Q)$ with $\alpha_s$ is fully taken into account. A new generation of CTEQ parton distributions, CTEQ4, is presented. It consists of the three standard sets (\mbox{\small {$\overline {\rm MS}$}}, {\protect \small DIS} and leading order), a series that gives a range of parton distributions with corresponding $\alpha_s$'s, and a set with a low starting value of $Q$. Previously obtained gluon distributions that are consistent with the high $E_t$ jet cross-section are also discussed in the context of this new global analysis.