| We present a measurement of the W boson charge asymmetry in pp¯ collisions using W → enu decays using 750 pb-1 of data collected with the DO detector at the Fermilab Tevatron. The electron coverage is extended to |eta| < 3.2 and is thus sensitive to Ws generated with low and high x partons. We also measured the charge asymmetry for events with electron ET > 25 GeV, 25 < ET < 35 GeV and E T > 35 GeV. By dividing events into different electron ET regions, we can probe different W boson rapidity regions, and can provide more constraints on the parton distribution functions (PDFs). Theoretical predictions made using CTEQ6.6 and MRST2004NLO PDFs are compared with the measurement. Our measurement is the most precise W charge asymmetry measurement to date, and this single measurement is superior in precision to the combined world average of all previous W charge asymmetry measurements done at the Tevatron. The measured asymmetry errors are less than the CTEQ6.6 PDF uncertainty for most rapidity bins. The inclusion of our results will further constrain future PDF fits and improve the predictions. |
