Recent Progress in Parton Distributions and Implications for LHC Physics

I outline some of the most recent developments in the global fit to parton distributions performed by the MRST collaboration. At present there is a great deal of interest in the importance of parton distributions for studies at the LHC. This necessarily involves a certain kinematic range for the partons. The kinematic range for particle production at the LHC is shown in fig. 1. Parton distributions at x ∼ 0.001− 0.01 are vital for understanding the standard production processes at the LHC. However, even smaller (and higher) x partons are required when one moves away from zero rapidity, e.g. when calculating the total production crosssection of the heavy boson. As well as the central values one needs the uncertainties on the partons, and there has been a lot of work on this [1]–[9]. This uncertainty is shown for the ū and d̄ quarks in fig. 2. Central rapidity production of W,Z Higgs at the LHC probes x = 0.006, which is ideal for the MRST partons. The current best 10 -7 10 -6 10 -5 10 -4 10 -3 10 -2 10 -1 10 0 10 0 10 1 10 2 10 3 10 4 10 5 10 6 10 7 10 8 10 9