content_image/373382.jpg
<img src='content_image/373382.jpg'>

(lepton pairs and W/Z bosons) production in pp [53] and p ¯ p collisions [54], jet data from Tevatron and data from many other experiments, especially low energy, are used to extract the PDFs using a global fit. These experiments are sensitive to different f$_{i}$ . For example, e $^{±}$p experiments are sensitive to the sum of the q and ¯ q distributions weighted by e 2 q (¯ q ) and can not distinguish between quark and anti-quark distributions. Neutrino and anti-neutrino data are used to differentiate between q and ¯ q . The Tevatron jet data play a significant 

