What does the W p_T distribution tell us about the W + 1 jet / W + 0 jet   ratio at the Tevatron ?
  We show that the W p_T distribution measured by D0 at the Tevatron agrees well with the NLO QCD theoretical prediction for this quantity, whilst the W + 1 jet/ W + 0 jet ratio, R^10, measured by D0 lies significantly above the NLO QCD theoretical prediction. We derive an approximate relationship between these two quantities, and show that this rules out the majority of theoretical explanations for the D0 excess in R^10. We discuss possible physics that could give rise to the R^10 excess, which have little effect on the W p_T. 
David J. Summers (Univ. of Cambridge)